1Menu(3) User Contributed Perl Documentation Menu(3)
2
6 Tk::Menu - Create and manipulate Menu widgets
7
9 $menu = $parent->Menu(?options?);
10
12 -activebackground -background -disabledforeground -relief
13 -activeborderwidth -borderwidth -font -takefocus
14 -activeforeground -cursor -foreground
15 See Tk::options for details of the standard options.
17
19 Name: postCommand
20 Class: Command
21 Switch: -postcommand
22 If this option is specified then it provides a callback to execute
23 each time the menu is posted. The callback is invoked by the post
24 method before posting the menu. Note that in 8.0 on Macintosh and
25 Windows, all commands in a menu systems are executed before any are
26 posted. This is due to the limitations in the individual platforms'
27 menu managers.
28 Name: selectColor
30 Class: Background
31 Switch: -selectcolor
32 For menu entries that are check buttons or radio buttons, this
33 option specifies the color to display in the indicator when the
34 check button or radio button is selected.
35 Name: tearOff
37 Class: TearOff
38 Switch: -tearoff
39 This option must have a proper boolean value, which specifies
40 whether or not the menu should include a tear-off entry at the top.
41 If so, it will exist as entry 0 of the menu and the other entries
42 will number starting at 1. The default menu bindings arrange for
43 the menu to be torn off when the tear-off entry is invoked.
44 Name: tearOffCommand
46 Class: TearOffCommand
47 Switch: -tearoffcommand
48 If this option has a non-empty value, then it specifies a perl/Tk
49 callback to invoke whenever the menu is torn off. The actual
50 command will consist of the value of this option, followed by a
51 space, followed by the name of the menu window, followed by a
52 space, followed by the name of the name of the torn off menu
53 window. For example, if the option's is ``a b'' and menu .x.y is
54 torn off to create a new menu .x.tearoff1, then the command ``a b
55 .x.y .x.tearoff1'' will be invoked.
56 Name: title
58 Class: Title
59 Switch: -title
60 The string will be used to title the window created when this menu
61 is torn off. If the title is NULL, then the window will have the
62 title of the menubutton or the text of the cascade item from which
63 this menu was invoked.
64 Name: type
66 Class: Type
67 Switch: -type
68 This option can be one of menubar, tearoff, or normal, and is set
69 when the menu is created. While the string returned by the
70 configuration database will change if this option is changed, this
71 does not affect the menu widget's behavior. This is used by the
72 cloning mechanism and is not normally set outside of the Tk
73 library.
74
76 The Menu method creates a new top-level window (given by the $widget
77 argument) and makes it into a menu widget. Additional options,
78 described above, may be specified on the command line or in the option
79 database to configure aspects of the menu such as its colors and font.
80 The menu command returns its $widget argument. At the time this
81 command is invoked, there must not exist a window named $widget, but
82 $widget's parent must exist.
83 A menu is a widget that displays a collection of one-line entries
85 arranged in one or more columns. There exist several different types
86 of entries, each with different properties. Entries of different types
87 may be combined in a single menu. Menu entries are not the same as
88 entry widgets. In fact, menu entries are not even distinct widgets;
89 the entire menu is one widget.
90 Menu entries are displayed with up to three separate fields. The main
92 field is a label in the form of a text string, a bitmap, or an image,
93 controlled by the -label, -bitmap, and -image options for the entry.
94 If the -accelerator option is specified for an entry then a second
95 textual field is displayed to the right of the label. The accelerator
96 typically describes a keystroke sequence that may be typed in the
97 application to cause the same result as invoking the menu entry. The
98 third field is an indicator. The indicator is present only for
99 checkbutton or radiobutton entries. It indicates whether the entry is
100 selected or not, and is displayed to the left of the entry's string.
101 In normal use, an entry becomes active (displays itself differently)
103 whenever the mouse pointer is over the entry. If a mouse button is
104 released over the entry then the entry is invoked. The effect of
105 invocation is different for each type of entry; these effects are
106 described below in the sections on individual entries.
107 Entries may be disabled, which causes their labels and accelerators to
109 be displayed with dimmer colors. The default menu bindings will not
110 allow a disabled entry to be activated or invoked. Disabled entries
111 may be re-enabled, at which point it becomes possible to activate and
112 invoke them again.
113 Whenever a menu's active entry is changed, a <<MenuSelect>> virtual
115 event is sent to the menu. The active item can then be queried from the
116 menu, and an action can be taken, such as setting context-sensitive
117 help text for the entry.
118 COMMAND ENTRIES
120 The most common kind of menu entry is a command entry, which behaves
121 much like a button widget. When a command entry is invoked, a callback
122 is executed. The callback is specified with the -command option.
123 SEPARATOR ENTRIES
125 A separator is an entry that is displayed as a horizontal dividing
126 line. A separator may not be activated or invoked, and it has no
127 behavior other than its display appearance.
128 CHECKBUTTON ENTRIES
130 A checkbutton menu entry behaves much like a checkbutton widget. When
131 it is invoked it toggles back and forth between the selected and
132 deselected states. When the entry is selected, a particular value is
133 stored in a particular global variable (as determined by the -onvalue
134 and -variable options for the entry); when the entry is deselected
135 another value (determined by the -offvalue option) is stored in the
136 global variable. An indicator box is displayed to the left of the
137 label in a checkbutton entry. If the entry is selected then the
138 indicator's center is displayed in the color given by the -selectcolor
139 option for the entry; otherwise the indicator's center is displayed in
140 the background color for the menu. If a -command option is specified
141 for a checkbutton entry, then its value is evaluated each time the
142 entry is invoked; this happens after toggling the entry's selected
143 state.
144 RADIOBUTTON ENTRIES
146 A radiobutton menu entry behaves much like a radiobutton widget.
147 Radiobutton entries are organized in groups of which only one entry may
148 be selected at a time. Whenever a particular entry becomes selected it
149 stores a particular value into a particular global variable (as
150 determined by the -value and -variable options for the entry). This
151 action causes any previously-selected entry in the same group to
152 deselect itself. Once an entry has become selected, any change to the
153 entry's associated variable will cause the entry to deselect itself.
154 Grouping of radiobutton entries is determined by their associated
155 variables: if two entries have the same associated variable then they
156 are in the same group. An indicator diamond is displayed to the left
157 of the label in each radiobutton entry. If the entry is selected then
158 the indicator's center is displayed in the color given by the
159 -selectcolor option for the entry; otherwise the indicator's center is
160 displayed in the background color for the menu. If a -command option
161 is specified for a radiobutton entry, then its value is evaluated each
162 time the entry is invoked; this happens after selecting the entry.
163 CASCADE ENTRIES
165 A cascade entry is one with an associated menu (determined by the -menu
166 option). Cascade entries allow the construction of cascading menus.
167 The postcascade method can be used to post and unpost the associated
168 menu just next to of the cascade entry. The associated menu must be a
169 child of the menu containing the cascade entry (this is needed in order
170 for menu traversal to work correctly).
171 A cascade entry posts its associated menu by invoking
173 $menu->post(x,y)
175 where menu is the path name of the associated menu, and x and y are the
177 root-window coordinates of the upper-right corner of the cascade entry.
178 On Unix, the lower-level menu is unposted by executing
179 $menu->unpost
181 where menu is the name of the associated menu. On other platforms, the
183 platform's native code takes care of unposting the menu.
184 If a -command option is specified for a cascade entry then it is
186 evaluated whenever the entry is invoked. This is not supported on
187 Windows.
188 TEAR-OFF ENTRIES
190 A tear-off entry appears at the top of the menu if enabled with the
191 tearOff option. It is not like other menu entries in that it cannot be
192 created with the add method and cannot be deleted with the delete
193 method. When a tear-off entry is created it appears as a dashed line
194 at the top of the menu. Under the default bindings, invoking the tear-
195 off entry causes a torn-off copy to be made of the menu and all of its
196 submenus.
197 MENUBARS
199 Any menu can be set as a menubar for a toplevel window (see the
200 Toplevel constructor for syntax). On the Macintosh, whenever the
201 toplevel is in front, this menu's cascade items will appear in the
202 menubar across the top of the main monitor. On Windows and Unix, this
203 menu's items will be displayed in a menubar accross the top of the
204 window. These menus will behave according to the interface guidelines
205 of their platforms. For every menu set as a menubar, a clone menu is
206 made. See "CLONES" for more information.
207 As noted, menubars may behave differently on different platforms. One
209 example of this concerns the handling of checkbuttons and radiobuttons
210 within the menu. While it is permitted to put these menu elements on
211 menubars, they may not be drawn with indicators on some platforms, due
212 to system restrictions.
213 SPECIAL MENUS IN MENUBARS
215 Certain menus in a menubar will be treated specially. On the
216 Macintosh, access to the special Apple and Help menus is provided. On
217 Windows, access to the Windows System menu in each window is provided.
218 On X Windows, a special right-justified help menu is provided. In all
219 cases, these menus must be created with the command name of the menubar
220 menu concatenated with the special name. So for a menubar named
221 .menubar, on the Macintosh, the special menus would be .menubar.apple
222 and .menubar.help; on Windows, the special menu would be
223 .menubar.system; on X Windows, the help menu would be .menubar.help.
224 When Tk sees an Apple menu on the Macintosh, that menu's contents make
226 up the first items of the Apple menu on the screen whenever the window
227 containing the menubar is in front. The menu is the first one that the
228 user sees and has a title which is an Apple logo. After all of the Tk-
229 defined items, the menu will have a separator, followed by all of the
230 items in the user's Apple Menu Items folder. Since the System uses a
231 different menu definition procedure for the Apple menu than Tk uses for
232 its menus, and the system APIs do not fully support everything Tk tries
233 to do, the menu item will only have its text displayed. No font
234 attributes, images, bitmaps, or colors will be displayed. In addition,
235 a menu with a tearoff item will have the tearoff item displayed as
236 "(TearOff)".
237 When Tk see a Help menu on the Macintosh, the menu's contents are
239 appended to the standard help menu on the right of the user's menubar
240 whenever the user's menubar is in front. The first items in the menu
241 are provided by Apple. Similar to the Apple Menu, cusomization in this
242 menu is limited to what the system provides.
243 When Tk sees a System menu on Windows, its items are appended to the
245 system menu that the menubar is attached to. This menu has an icon
246 representing a spacebar, and can be invoked with the mouse or by typing
247 Alt+Spacebar. Due to limitations in the Windows API, any font changes,
248 colors, images, bitmaps, or tearoff images will not appear in the
249 system menu.
250 When Tk see a Help menu on X Windows, the menu is moved to be last in
252 the menubar and is right justified.
253 CLONES
255 When a menu is set as a menubar for a toplevel window, or when a menu
256 is torn off, a clone of the menu is made. This clone is a menu widget
257 in its own right, but it is a child of the original. Changes in the
258 configuration of the original are reflected in the clone. Additionally,
259 any cascades that are pointed to are also cloned so that menu traversal
260 will work right. Clones are destroyed when either the tearoff or
261 menubar goes away, or when the original menu is destroyed.
262 WIDGET METHODS
264 The Menu method creates a widget object. This object supports the
265 configure and cget methods described in Tk::options which can be used
266 to enquire and modify the options described above. The widget also
267 inherits all the methods provided by the generic Tk::Widget class, and
268 the Tk::Wm class.
269 Many of the methods for a menu take as one argument an indicator of
271 which entry of the menu to operate on. These indicators are called
272 indexes and may be specified in any of the following forms:
273 number
275 Specifies the entry numerically, where 0 corresponds to the top-
276 most entry of the menu, 1 to the entry below it, and so on.
277 active
279 Indicates the entry that is currently active. If no entry is
280 active then this form is equivalent to none. This form may not be
281 abbreviated.
282 end Indicates the bottommost entry in the menu. If there are no
284 entries in the menu then this form is equivalent to none. This
285 form may not be abbreviated.
286 last
288 Same as end.
289 none
291 Indicates ``no entry at all''; this is used most commonly with the
292 activate option to deactivate all the entries in the menu. In most
293 cases the specification of none causes nothing to happen in the
294 method. This form may not be abbreviated.
295 @number
297 In this form, number is treated as a y-coordinate in the menu's
298 window; the entry closest to that y-coordinate is used. For
299 example, ``@0'' indicates the top-most entry in the window.
300 pattern
302 If the index doesn't satisfy one of the above forms then this form
303 is used. Pattern is pattern-matched against the label of each
304 entry in the menu, in order from the top down, until a matching
305 entry is found. (In perl/Tk the matching is under review, but
306 exact match should work.)
307 The following methods are possible for menu widgets:
309 $menu->activate(index)
311 Change the state of the entry indicated by index to active and
312 redisplay it using its active colors. Any previously-active entry
313 is deactivated. If index is specified as none, or if the specified
314 entry is disabled, then the menu ends up with no active entry.
315 Returns an empty string.
316 $menu->add(type, ?option, value, option, value, ...?)
318 Add a new entry to the bottom of the menu. The new entry's type is
319 given by type and must be one of cascade, checkbutton, command,
320 radiobutton, or separator, or a unique abbreviation of one of the
321 above. If additional arguments are present, they specify any of
322 the following options:
323 -activebackground => value
325 Specifies a background color to use for displaying this
326 entry when it is active. If this option is specified as an
327 empty string (the default), then the activeBackground
328 option for the overall menu is used. If the
329 $Tk::strictMotif variable has been set to request strict
330 Motif compliance, then this option is ignored and the
331 -background option is used in its place. This option is
332 not available for separator or tear-off entries.
333 -activeforeground => value
335 Specifies a foreground color to use for displaying this
336 entry when it is active. If this option is specified as an
337 empty string (the default), then the activeForeground
338 option for the overall menu is used. This option is not
339 available for separator or tear-off entries.
340 -accelerator => value
342 Specifies a string to display at the right side of the menu
343 entry. Normally describes an accelerator keystroke
344 sequence that may be typed to invoke the same function as
345 the menu entry. This option is not available for separator
346 or tear-off entries.
347 -background => value
349 Specifies a background color to use for displaying this
350 entry when it is in the normal state (neither active nor
351 disabled). If this option is specified as an empty string
352 (the default), then the background option for the overall
353 menu is used. This option is not available for separator
354 or tear-off entries.
355 -bitmap => value
357 Specifies a bitmap to display in the menu instead of a
358 textual label, in any of the forms accepted by
359 Tk_GetBitmap. This option overrides the -label option but
360 may be reset to an empty string to enable a textual label
361 to be displayed. If a -image option has been specified, it
362 overrides -bitmap. This option is not available for
363 separator or tear-off entries.
364 -columnbreak => value
366 When this option is zero, the appears below the previous
367 entry. When this option is one, the menu appears at the top
368 of a new column in the menu.
369 -compound => value
371 Specifies whether the button should display both an image
372 and text, and if so, where the image should be placed
373 relative to the text. Valid values for this option are
374 bottom, center, left, none, right and top. The default
375 value is none, meaning that the button will display either
376 an image or text, depending on the values of the -image and
377 -bitmap options.
378 -command => value
380 For command, checkbutton, and radiobutton entries,
381 specifies a callback to execute when the menu entry is
382 invoked. For cascade entries, specifies a callback to
383 execute when the entry is activated (i.e. just before its
384 submenu is posted). Not available for separator or tear-
385 off entries.
386 -font => value
388 Specifies the font to use when drawing the label or
389 accelerator string in this entry. If this option is
390 specified as an empty string (the default) then the font
391 option for the overall menu is used. This option is not
392 available for separator or tear-off entries.
393 -foreground => value
395 Specifies a foreground color to use for displaying this
396 entry when it is in the normal state (neither active nor
397 disabled). If this option is specified as an empty string
398 (the default), then the foreground option for the overall
399 menu is used. This option is not available for separator
400 or tear-off entries.
401 -hidemargin => value
403 Specifies whether the standard margins should be drawn for
404 this menu entry. This is useful when creating palette with
405 images in them, i.e., color palettes, pattern palettes,
406 etc. 1 indicates that the margin for the entry is hidden; 0
407 means that the margin is used.
408 -image => value
410 Specifies an image to display in the menu instead of a text
411 string or bitmap The image must have been created by some
412 previous invocation of image create. This option overrides
413 the -label and -bitmap options but may be reset to an empty
414 string to enable a textual or bitmap label to be displayed.
415 This option is not available for separator or tear-off
416 entries.
417 -indicatoron => value
419 Available only for checkbutton and radiobutton entries.
420 Value is a boolean that determines whether or not the
421 indicator should be displayed.
422 -label => value
424 Specifies a string to display as an identifying label in
425 the menu entry. Not available for separator or tear-off
426 entries.
427 -menu => value
429 Available only for cascade entries. Specifies the path
430 name of the submenu associated with this entry. The
431 submenu must be a child of the menu.
432 -offvalue => value
434 Available only for checkbutton entries. Specifies the
435 value to store in the entry's associated variable when the
436 entry is deselected.
437 -onvalue => value
439 Available only for checkbutton entries. Specifies the
440 value to store in the entry's associated variable when the
441 entry is selected.
442 -selectcolor => value
444 Available only for checkbutton and radiobutton entries.
445 Specifies the color to display in the indicator when the
446 entry is selected. If the value is an empty string (the
447 default) then the selectColor option for the menu
448 determines the indicator color.
449 -selectimage => value
451 Available only for checkbutton and radiobutton entries.
452 Specifies an image to display in the entry (in place of the
453 -image option) when it is selected. Value is the name of
454 an image, which must have been created by some previous
455 invocation of image create. This option is ignored unless
456 the -image option has been specified.
457 -state => value
459 Specifies one of three states for the entry: normal,
460 active, or disabled. In normal state the entry is
461 displayed using the foreground option for the menu and the
462 background option from the entry or the menu. The active
463 state is typically used when the pointer is over the entry.
464 In active state the entry is displayed using the
465 activeForeground option for the menu along with the
466 activebackground option from the entry. Disabled state
467 means that the entry should be insensitive: the default
468 bindings will refuse to activate or invoke the entry. In
469 this state the entry is displayed according to the
470 disabledForeground option for the menu and the background
471 option from the entry. This option is not available for
472 separator entries.
473 -underline => value
475 Specifies the integer index of a character to underline in
476 the entry. This option is also queried by the default
477 bindings and used to implement keyboard traversal. 0
478 corresponds to the first character of the text displayed in
479 the entry, 1 to the next character, and so on. If a bitmap
480 or image is displayed in the entry then this option is
481 ignored. This option is not available for separator or
482 tear-off entries.
483 -value => value
485 Available only for radiobutton entries. Specifies the
486 value to store in the entry's associated variable when the
487 entry is selected. If an empty string is specified, then
488 the -label option for the entry as the value to store in
489 the variable.
490 -variable => value
492 Available only for checkbutton and radiobutton entries.
493 Specifies the name of a global value to set when the entry
494 is selected. For checkbutton entries the variable is also
495 set when the entry is deselected. For radiobutton entries,
496 changing the variable causes the currently-selected entry
497 to deselect itself.
498 The add method returns an empty string.
500 $menu->clone($parent ?, cloneType?)
502 Makes a clone of the current menu as a child of $parent. This clone
503 is a menu in its own right, but any changes to the clone are
504 propogated to the original menu and vice versa. cloneType can be
505 normal, menubar, or tearoff. Should not normally be called outside
506 of the Tk library. See "CLONES" for more information.
507 $menu->delete(index1?, index2?)
509 Delete all of the menu entries between index1 and index2 inclusive.
510 If index2 is omitted then it defaults to index1. Attempts to
511 delete a tear-off menu entry are ignored (instead, you should
512 change the tearOff option to remove the tear-off entry).
513 $menu->entrycget(index, option)
515 Returns the current value of a configuration option for the entry
516 given by index. Option may have any of the values accepted by the
517 add method.
518 $menu->entryconfigure(index ?,options?)
520 This method is similar to the configure method, except that it
521 applies to the options for an individual entry, whereas configure
522 applies to the options for the menu as a whole. Options may have
523 any of the values accepted by the add method. If options are
524 specified, options are modified as indicated in the method call and
525 the method returns an empty string. If no options are specified,
526 returns a list describing the current options for entry index (see
527 Tk::options for information on the format of this list).
528 $menu->index(index)
530 Returns the numerical index corresponding to index, or none if
531 index was specified as none.
532 $menu->insert(index, type?, -option=>value, ...?)
534 Same as the add method except that it inserts the new entry just
535 before the entry given by index, instead of appending to the end of
536 the menu. The type, -option, and value arguments have the same
537 interpretation as for the add widget method. It is not possible to
538 insert new menu entries before the tear-off entry, if the menu has
539 one.
540 $menu->invoke(index)
542 Invoke the action of the menu entry. See the sections on the
543 individual entries above for details on what happens. If the menu
544 entry is disabled then nothing happens. If the entry has a
545 callback associated with it then the result of that callback is
546 returned as the result of the invoke widget method. Otherwise the
547 result is an empty string. Note: invoking a menu entry does not
548 automatically unpost the menu; the default bindings normally take
549 care of this before invoking the invoke method.
550 $menu->post(x, y)
552 Arrange for the menu to be displayed on the screen at the root-
553 window coordinates given by x and y. These coordinates are
554 adjusted if necessary to guarantee that the entire menu is visible
555 on the screen. This method normally returns an empty string. If
556 the postCommand option has been specified, then its value is
557 executed before posting the menu and the result of that callback is
558 returned as the result of the post widget method. If an error
559 returns while executing the method, then the error is returned
560 without posting the menu.
561 $menu->postcascade(index)
563 Posts the submenu associated with the cascade entry given by index,
564 and unposts any previously posted submenu. If index doesn't
565 correspond to a cascade entry, or if $menu isn't posted, the method
566 has no effect except to unpost any currently posted submenu.
567 $menu->type(index)
569 Returns the type of the menu entry given by index. This is the
570 type argument passed to the add widget method when the entry was
571 created, such as command or separator, or tearoff for a tear-off
572 entry.
573 $menu->unpost
575 Unmap the window so that it is no longer displayed. If a lower-
576 level cascaded menu is posted, unpost that menu. Returns an empty
577 string. This method does not work on Windows and the Macintosh, as
578 those platforms have their own way of unposting menus.
579 $menu->yposition(index)
581 Returns a decimal string giving the y-coordinate within the menu
582 window of the topmost pixel in the entry specified by index.
583
585 The default bindings support four different ways of using menus:
586 Pulldown Menus in Menubar
588 This is the most command case. You create a menu widget that will
589 become the menu bar. You then add cascade entries to this menu,
590 specifying the pull down menus you wish to use in your menu bar.
591 You then create all of the pulldowns. Once you have done this,
592 specify the menu using the -menu option of the toplevel's method.
593 See the toplevel manual entry for details.
594 Pulldown Menus in Menu Buttons
596 This is the compatable way to do menu bars. You create one
597 menubutton widget for each top-level menu, and typically you
598 arrange a series of menubuttons in a row in a menubar window. You
599 also create the top-level menus and any cascaded submenus, and tie
600 them together with -menu options in menubuttons and cascade menu
601 entries. The top-level menu must be a child of the menubutton, and
602 each submenu must be a child of the menu that refers to it. Once
603 you have done this, the default bindings will allow users to
604 traverse and invoke the tree of menus via its menubutton; see the
605 menubutton documentation for details.
606 Popup Menus
608 Popup menus typically post in response to a mouse button press or
609 keystroke. You create the popup menus and any cascaded submenus,
610 then you call the Post method at the appropriate time to post the
611 top-level menu.
612 $menu->Post($x,$y?,$entry?)
614 $x and $y are the root window coordinates at which the $menu will
616 be displayed. If $entry is specified then that entry is centred on
617 that point, otherwise the top-left corner of the $menu is placed at
618 that point.
619 Menu also inherits methods from Tk::Wm and so the method Popup can
621 be used to position menu relative to other windows, the mouse
622 cursor or the screen.
623 Option Menus
625 An option menu consists of a menubutton with an associated menu
626 that allows you to select one of several values. The current value
627 is displayed in the menubutton and is also stored in a global
628 variable. Use the Tk::Optionmenu class to create option
629 menubuttons and their menus.
630 Torn-off Menus
632 You create a torn-off menu by invoking the tear-off entry at the
633 top of an existing menu. The default bindings will create a new
634 menu that is a copy of the original menu and leave it permanently
635 posted as a top-level window. The torn-off menu behaves just the
636 same as the original menu.
637
639 Tk automatically creates class bindings for menus that give them the
640 following default behavior:
641 [1] When the mouse enters a menu, the entry underneath the mouse cursor
643 activates; as the mouse moves around the menu, the active entry
644 changes to track the mouse.
645 [2] When the mouse leaves a menu all of the entries in the menu
647 deactivate, except in the special case where the mouse moves from a
648 menu to a cascaded submenu.
649 [3] When a button is released over a menu, the active entry (if any) is
651 invoked. The menu also unposts unless it is a torn-off menu.
652 [4] The Space and Return keys invoke the active entry and unpost the
654 menu.
655 [5] If any of the entries in a menu have letters underlined with with
657 -underline option, then pressing one of the underlined letters (or
658 its upper-case or lower-case equivalent) invokes that entry and
659 unposts the menu.
660 [6] The Escape key aborts a menu selection in progress without invoking
662 any entry. It also unposts the menu unless it is a torn-off menu.
663 [7] The Up and Down keys activate the next higher or lower entry in the
665 menu. When one end of the menu is reached, the active entry wraps
666 around to the other end.
667 [8] The Left key moves to the next menu to the left. If the current
669 menu is a cascaded submenu, then the submenu is unposted and the
670 current menu entry becomes the cascade entry in the parent. If the
671 current menu is a top-level menu posted from a menubutton, then the
672 current menubutton is unposted and the next menubutton to the left
673 is posted. Otherwise the key has no effect. The left-right order
674 of menubuttons is determined by their stacking order: Tk assumes
675 that the lowest menubutton (which by default is the first one
676 created) is on the left.
677 [9] The Right key moves to the next menu to the right. If the current
679 entry is a cascade entry, then the submenu is posted and the
680 current menu entry becomes the first entry in the submenu.
681 Otherwise, if the current menu was posted from a menubutton, then
682 the current menubutton is unposted and the next menubutton to the
683 right is posted.
684 Disabled menu entries are non-responsive: they don't activate and
686 they ignore mouse button presses and releases.
687 The behavior of menus can be changed by defining new bindings for
689 individual widgets or by redefining the class bindings.
690
692 At present it isn't possible to use the option database to specify
693 values for the options to individual entries.
694
696 Tk::callbacks
697
699 menu, widget
700perl v5.28.0 2018-07-15 Menu(3)