NAME
XmComboBox — The ComboBox widget class
SYNOPSIS
#include <Xm/ComboBox.h>
DESCRIPTION
XmComboBox combines the capabilities of a single-line TextField widget
and a List widget. It allows users to perform opoerations like typing
and pasting information, and it also provides a list of possible
choices that the user can select from to complete the TextField entry
field. The list can either be displayed at all times or can be dropped
down by the user. When the list portion of the ComboBox is hidden,
users are given a visual cue (a downward-pointing arrow) next to the
TextField field. The position of the arrow relative to the TextField
field depends on the XmNlayoutDirection resource of the widget. This
version of the ComboBox is called the "drop-down" ComboBox. Drop-down
ComboBoxes are useful when screen space is limited, or when users will
complete the text entry field more often by typing text than by
selecting the entry field text from the list. The user can access the
drop-down ComboBox in either one of two ways:
· By clicking and releasing <Btn1> on the downward-pointing arrow,
which pops the list up, and the list stays up. A later selection
of an item in the list will cause the item to appear in the text
entry field, and the list will unpost itself.
· By pressing <Btn1> on the downward-pointing arrow, dragging it to
a list item, and then releasing it there, which selects that
item. The list disappears, and the selected item appears in the
text entry field.
The application provides an array of strings that fill the list. At
creation time, string items can be passed to the ComboBox via an
arglist. Each string becomes an item in the list, with the first
string becoming the item in position 1, the second string becoming the
item in position 2, and so on. The size of the list is set by
specifying the number of items that are visible in the list
(XmNvisibleItemCount). If the number of items in the list exceeds the
number of items that are visible, a vertical scroll bar will
automatically appear that allows the user to scroll through a large
number of items.
ComboBox creates two child widgets: a TextField widget for entering
text and a ScrolledWindow containing a List for the list of items. The
name of the items list itself is List, and the name of the TextField is
Text. The application or user can specify resource values for these
widgets in a resource file, and the application can use XtNameToWidget
(specifying "*List" for the items list or "*Text" for the TextField
widget) to obtain the widget IDs of the descendant widgets. At
creation time, ComboBox passes appropriate resource values in the
creation arglist, including XmNitems, to the items list. Note that the
result of providing the XmNdestroyCallback resource in the creation
arglist is unspecified. The application should use the XtAddCallback
function to add callbacks to the appropriate widget (TextField or List)
after creating it.
ComboBox forces the following resource values on its List child:
· If XmNcomboBoxType is XmCOMBO_BOX, XmNtraversalOn is forced to
False.
· XmNhighlightThickness is forced to 2 in a drop-down ComboBox and
to 0 in other types of ComboBoxes.
· XmNborderWidth is forced to 0.
· XmNnavigationType is forced to XmNONE.
· XmNselectionPolicy is forced to XmBROWSE_SELECT.
· XmNlistSizePolicy is forced to XmVARIABLE.
· XmNspacing is forced to 0.
· XmNvisualPolicy is forced to XmVARIABLE.
· XmNselectedPositions is forced to NULL.
· XmNselectedPositionsCount is forced to 0.
When XmNcomboBoxType is XmDROP_DOWN_LIST, ComboBox forces the following
resource values on its TextField child:
· XmNeditable is forced to False.
· XmNcursorPositionVisible is forced to False.
· XmNshadowThickness is forced to 0.
By contrast, when XmNcomboBoxType is XmCOMBO_BOX or
XmDROP_DOWN_COMBO_BOX, ComboBox forces the following resource values on
its TextField child:
· XmNeditable is forced to True.
· XmNcursorPositionVisible is forced to True.
· XmNeditMode is forced to XmSINGLE_LINE_EDIT.
ComboBox always forces the values of the following resources on the
TextField:
· XmNnavigationType is forced to XmNONE.
· XmNhighlightThickness is forced to 0.
· XmNborderWidth is forced to 0.
ComboBox allows a single item to be selected in two ways: by selecting
the desired item from the List or by entering text into the TextField.
ComboBox does not automatically select a list item if the user types
that string into the TextField. It selects the item when the user
presses KActivate or moves the focus. ComboBox supports the Browse
Select selection model of List (see the XmList reference page for a
description of this model), so selections are mutually exclusive.
Selecting an item from the list causes that item to be displayed in the
TextField portion of the ComboBox. If an application sets the XmNvalue
resource of TextField, that string is shown in the TextField. If the
application has not provided any list items, or if there is no current
selection, the TextField is empty.
The TextField in the ComboBox widget can be either editable or
noneditable, depending on the value of the XmNcomboBoxType resource.
If the TextField is editable, the user can type into it. When the user
presses the Return key, the ComboBox will compare the typed entry to
the items in the List. If there is an exact match, then the matched
List item is selected. If the application wishes to validate the
entered text (for example, to ensure that the typed selection is a
valid one), it can do so by setting XmNmodifyVerifyCallback on the
TextField widget.
If the TextField is noneditable, typing text may invoke a matching
algorithm that will attempt to match the entered text with items in the
list. The specific matching algorithm applied, which may be none, is
determined by the value of the XmNmatchBehavior resource in ComboBox,
which can be either XmNONE or XmQUICK_NAVIGATE. A value of XmNONE
indicates that no matching algorithm will occur. A value of
XmQUICK_NAVIGATE indicates that when the List widget has focus, one-
character navigation is supported. In this algorithm, if the typed
character is the initial character of some item in the List, this
algorithm causes that item to be navigated to and selected, and the
item is displayed in the TextField. Subsequently typing the same
character will cycle among the items with the same first character.
Regardless of the selection mechanism used (either selected directly
from the List or typed into the TextField), when an item in the List is
selected, that item is highlighted in the List. In addition, the
selected item is displayed in the TextField of the ComboBox. If the
user performs an action that would move focus away from ComboBox, or
selects a List item, the XmNselectionCallback callbacks are invoked to
notify the application of the current contents of the TextField (or
choice). The application then takes whatever action is required based
on those contents (or choice).
ComboBox uses the XmQTspecifyRenderTable trait and holds the
XmQTaccessTextual trait.
Classes
XmComboBox inherits behavior, resources, and traits from Core,
Composite, and XmManager classes.
The class pointer is xmComboBoxWidgetClass.
The class name is XmComboBox.
New Resources
The following table defines a set of widget resources used by the
programmer to specify data. The programmer can also set the resource
values for the inherited classes to set attributes for this widget. To
reference a resource by name or by class in a .Xdefaults file, remove
the XmN or XmC prefix and use the remaining letters. To specify one of
the defined values for a resource in a .Xdefaults file, remove the Xm
prefix and use the remaining letters (in either lowercase or uppercase,
but include any underscores between words). The codes in the access
column indicate if the given resource can be at creation time (C), set
by using XtSetValues (S), retrieved by using XtGetValues (G), or is not
applicable (N/A).
+---------------------------------------------------------------------------------------+
| | XmComboBox Resource Set | | |
|Name | Class | Type | Default | Access |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNarrowSize | XmCArrowSize | Dimension | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNarrowSpacing | XmCArrowSpacing | Dimension | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNcolumns | XmCColumn | short | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNcomboBoxType | XmCComboBoxType | unsigned char | XmCOMBO_BOX | CG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNfontList | XmCFontList | XmFontList | NULL | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNhighlightThickness | XmCHighlightThickness | Dimension | 2 | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNitemCount | XmCItemCount | int | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNitems | XmCItems | XmStringTable | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNlist | XmCList | Widget | dynamic | G |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNmarginHeight | XmCMarginHeight | Dimension | 2 | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNmarginWidth | XmCMarginWidth | Dimension | 2 | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNmatchBehavior | XmCMatchBehavior | unsigned char | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNpositionMode | XmCPositionMode | XtEnum | XmZERO_BASED | CG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNrenderTable | XmCRenderTable | XmRenderTable | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNselectedItem | XmCSelectedItem | XmString | NULL | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNselectedPosition | XmCSelectedPosition | int | dynamic | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNselectionCallback | XmCCallback | XmCallbackList | NULL | C |
+----------------------+-----------------------+----------------+--------------+--------+
|XmtextField | XmCTextField | Widget | dynamic | G |
+----------------------+-----------------------+----------------+--------------+--------+
|XmNvisibleItemCount | XmCVisibleItemCount | int | 10 | CSG |
+----------------------+-----------------------+----------------+--------------+--------+
+----------------------+-----------------------+----------------+--------------+--------+
XmNarrowSize
Specifies the width of the arrow. The default size depends on
the size of the text, as well as the size of the ComboBox.
XmNarrowSpacing
Specifies the space between the text and arrow visual in
pixels. The default value is obtained from the XmNmarginWidth
resource.
XmNcolumns
Specifies the number of columns in the text field. If unset,
the text field’s value is used. Refer to the XmTextField man
page for more detailed information.
XmNcomboBoxType
Specifies the type of ComboBox to be created. This can be one
of the following:
XmCOMBO_BOX
Generates a ComboBox where the list is always
displayed, and the text entry field is editable.
XmDROP_DOWN_COMBO_BOX
Generates a ComboBox where the list is hidden
unless specifically requested, and the text entry
field is editable.
XmDROP_DOWN_LIST
Generates a ComboBox where the list is hidden
unless specifically requested, and the text entry
field is noneditable.
XmNfontList
Specifies the fontlist associated with XmComboBox. The
fontlist is an obsolete construct, and has been superseded by
the render table. It is included for compatibility with
earlier versions of Motif, and for applications that do not
easily support render tables. The default fontlist is derived
from the default render table, and if both a fontlist and a
render table are specified, the render table takes
precedence.
XmNhighlightThickness
Specifies the thickness of the highlighting rectangle.
XmNitemCount
Specifies the number of items in the list. If unset, the
lists’s value is used. Refer to the XmList man page for more
detailed information.
XmNitems Specifies the items in the list. If unset, the lists’s value
is used. Refer to the XmList man page for more detailed
information.
XmNlist The list widget.
XmNmarginWidth
Specifies the horizontal spacing between the child widgets
and the boundary of the ComboBox.
XmNmarginHeight
Specifies the vertical spacing between the child widgets and
the boundary of the ComboBox.
XmNmatchBehavior
Defines the matching algorithm applied to match the text
typed by the user in the TextField field with items in the
list. The current values are XmNONE and XmQUICK_NAVIGATE, as
follows:
XmNONE Indicates that there is no assigned matching
algorithm.
XmQUICK_NAVIGATE
Is only valid for noneditable ComboBoxes
(XmNcomboBoxType resource value XmDROP_DOWN_LIST).
This algorithm supports 1-character navigation when
the List widget has focus. If the typed character
is the initial character of some item in the List,
this algorithm causes that item to be navigated to
and selected. Subsequently typing the same
character will cycle among the items with the same
first character.
XmNpositionMode
Specifies how the value of the XmNselectedPosition resource
and the item_position field of the callback structure are to
be interpreted. Note that the convenience functions
XmComboBoxDeletePos and XmComboBoxAddItem are not affected by
this resource, and (like XmList) always use 1-based
positions. Valid values for this resource are:
XmZERO_BASED
(DtComboBox compatibility mode: default)
XmNselectedPosition is in [0,itemcount-1]. The
item_position in the XmComboBoxCallbackStruct is 0
if the first element in the list was selected. Note
that 0 is also returned if no element in the list
was selected (that is, a new item was entered in
the text field).
XmONE_BASED
(Motif mode) Both the resource value and the
callback fields are 1-based. This is consistent
with other Motif widgets.
XmNrenderTable
Specifies the render table associated with ComboBox. This
render table is used in both the TextField field and the List
in the ComboBox. This is used in conjunction with the
XmNvisibleItemCount resource of the List to determine the
height of the ComboBox widget.
If this value is NULL at initialization, and if the widget
parent is XmBulletinBoard or its subclasses, VendorShell or
its subclasses, or XmMenuShell, then the widget parent
provides the default render table associated with the widget.
If both a render table and a fontlist are specified, the
render table will take precedence.
XmNselectedItem
Specifies a compound string that represents the current
selection of the ComboBox. The selected item is the content
of the ComboBox text entry field.
XmNselectedPosition
If the selection in the ComboBox is an item in the list, this
is the index of the selected item in the list. If no item in
the list is selected, this is 0.
XmNselectionCallback
Specifies the list of callbacks called when an item is
selected. The reason field in the XmComboBoxCallbackStruct
is XmCR_SELECT.
XmNtextField
The text field widget.
XmNvisibleItemCount
Specifies the number of visible items in the list. This will
override any value specified for the list. Refer to the
XmList man page for more detailed information.
Inherited Resources
ComboBox inherits behavior and resources from superclasses described in
the following tables. For a complete description of each resource,
refer to the reference page for that superclass.
+----------------------------------------------------------------------------------------------------+
| | XmManager Resource Set | | |
|Name | Class | Type | Default | Access |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNbottomShadowColor | XmCBottomShadowColor | Pixel | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNbottomShadowPixmap | XmCBottomShadowPixmap | Pixmap | XmUNSPECIFIED_PIXMAP | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNforeground | XmCForeground | Pixel | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNhelpCallback | XmCCallback | XtCallbackList | NULL | C |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNhighlightColor | XmCHighlightColor | Pixel | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNhighlightPixmap | XmCHighlightPixmap | Pixmap | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNinitialFocus | XmCInitialFocus | Widget | NULL | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNlayoutDirection | XmCLayoutDirection | XmDirection | dynamic | CG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNnavigationType | XmCNavigationType | XmNavigationType | XmSTICKY_TAG_GROUP | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNpopupHandlerCallback | XmCCallback | XtCallbackList | NULL | C |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNshadowThickness | XmCShadowThickness | Dimension | 2 | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNstringDirection | XmCStringDirection | XmStringDirection | dynamic | CG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNtopShadowColor | XmCTopShadowColor | Pixel | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNtopShadowPixmap | XmCTopShadowPixmap | Pixmap | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNtraversalOn | XmCTraversalOn | Boolean | True | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNunitType | XmCUnitType | unsigned char | dynamic | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
|XmNuserData | XmCUserData | XtPointer | NULL | CSG |
+------------------------+-----------------------+-------------------+----------------------+--------+
+------------------------+-----------------------+-------------------+----------------------+--------+
+-----------------------------------------------------------------------+
| | Composite Resource Set | | |
|Name | Class | Type | Default | Access |
+------------------+-------------------+-------------+---------+--------+
|XmNchildren | XmCReadOnly | WidgetList | NULL | G |
+------------------+-------------------+-------------+---------+--------+
|XmNinsertPosition | XmCInsertPosition | XtOrderProc | NULL | CSG |
+------------------+-------------------+-------------+---------+--------+
|XmNnumChildren | XmCReadOnly | Cardinal | 0 | G |
+------------------+-------------------+-------------+---------+--------+
+------------------+-------------------+-------------+---------+--------+
+---------------------------------------------------------------------------------------------------------------+
| | Core Resource Set | | |
|Name | Class | Type | Default | Access |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNaccelerators | XmCAccelerators | XtAccelerators | dynamic | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNancestorSensitive | XmCSensitive | Boolean | dynamic | G |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNbackground | XmCBackground | Pixel | dynamic | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNbackgroundPixmap | XmCPixmap | Pixmap | XmUNSPECIFIED_PIXMAP | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNborderColor | XmCBorderColor | Pixel | XtDefaultForeground | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNborderPixmap | XmCPixmap | Pixmap | XmUNSPECIFIED_PIXMAP | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNborderWidth | XmCBorderWidth | Dimension | 0 | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNcolormap | XmCColormap | Colormap | dynamic | CG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNdepth | XmCDepth | int | dynamic | CG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNdestroyCallback | XmCCallback | XtCallbackList | NULL | C |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNheight | XmCHeight | Dimension | dynamic | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNinitialResourcesPersistent | XmCInitialResourcesPersistent | Boolean | True | C |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNmappedWhenManaged | XmCMappedWhenManaged | Boolean | True | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNscreen | XmCScreen | Screen * | dynamic | CG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNsensitive | XmCSensitive | Boolean | True | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNtranslations | XmCTranslations | XtTranslations | dynamic | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNwidth | XmCWidth | Dimension | dynamic | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNx | XmCPosition | Position | 0 | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
|XmNy | XmCPosition | Position | 0 | CSG |
+------------------------------+-------------------------------+----------------+----------------------+--------+
+------------------------------+-------------------------------+----------------+----------------------+--------+
Callback Information
A pointer to the following structure is passed to each callback. The
callback structure is defined as follows:
typedef struct
{
int reason;
XEvent *event;
XmString item_or_text;
int item_position;
} XmComboBoxCallbackStruct;
reason Indicates why the callback was invoked.
event Points to the XEvent that triggered the callback. It can be
NULL.
item_or_text
The contents of the text field at the time the event caused
the callback. The item_or_text parameter points to a
temporary storage space that is reused after the callback is
finished. If an application needs to save the item, it should
copy item_or_text into its own data space.
item_position
The position of item in the list’s XmNitems 1-based array. If
this is 0, it means that the item_or_text was not selected
from the List.
Translations
The ComboBox translations are listed below.
The following key names are listed in the X standard key event
translation table syntax. This format is the one used by Motif to
specify the widget actions corresponding to a given key. A brief
overview of the format is provided under VirtualBindings(3). For a
complete description of the format, please refer to the X Toolkit
Instrinsics Documentation.
Note:
The KPageUp and KPageDown translations do not take effect unless
the List child widget is posted.
<Btn1Down>:
CBArmAndDropDownList()
<Btn1Up>: CBDisarm()
The following lists the List translations in the drop-down list. When
ComboBox XmNcomboBoxType is XmDROP_DOWN_LIST, <osfActivate>,
<osfCancel>, and Return are overriden by ComboBox actions.
:c <Key><osfDown>:
CBDropDownList()
:c <Key><osfUp>:
CBDropDownList()
:<Key><osfCancel>:
CBCancel()
:<Key><osfActivate>:
CBActivate()
∼s ∼m ∼a<Key>Return:
CBActivate()
Accelerators
The following accelerators are added to ComboBox and its children. The
accelerators may not directly correspond to a translation table. If
the translation is not listed below, it may depend on the context of
the event.
:c <Key><osfUp>:
CBDropDownList()
:<Key><osfUp>:
CBListAction(Up)
:c <Key><osfDown>:
CBDropDownList()
:<Key><osfDown>:
CBListAction(Down)
:c <Key><osfBeginLine>:
CBListAction(ListBeginData)
:c <Key><osfEndLine>:
CBListAction(ListEndData)
:<Key><osfPageUp>:
CBListAction(ListPrevPage)
:<Key><osfPageDown>:
CBListAction(ListNextPage)
A drop-down ComboBox also adds accelerators to its List child. Aside
from the accelerators that are already listed in this section, those
accelerators are the default TextField key translations.
Action Routines
The XmComboBox action routines are as follows:
CBActivate():
Calls the XmNselectionCallback callbacks. If the
XmNcomboBoxType is XmDROP_DOWN_COMBO_BOX or XmDROP_DOWN_LIST,
it unposts the list. If the parent is a manager, passes the
event to the parent.
CBArmAndDropDownList():
If the pointer is within the down arrow, draws the shadow of
the arrow in the selected state, and then posts the list.
CBCancel():
If the XmNcomboBoxType is XmDROP_DOWN_COMBO_BOX or
XmDROP_DOWN_LIST, pops down the list. If the parent is a
manager, passes the event to the parent.
CBDisarm():
Redraws the arrow in an unselected state.
CBDropDownList():
If XmNcomboBoxType is XmDROP_DOWN or XmDROP_DOWN_LIST, and
list is not displayed, posts the list. If list is displayed,
it unposts the list.
CBListAction(ListBeginData):
Moves the location cursor to the first item in the list. In
Normal Mode, this also deselects any current selection,
selects the first item in the list, and calls the
XmNbrowseSelectionCallback selection callback.
CBListAction(ListEndData):
Moves the location cursor to the last item in the list. In
Normal Mode, this also deselects any current selection,
selects the last item in the list, and calls the
XmNbrowseSelectionCallback selection callback.
CBListAction(ListPrevPage):
Scrolls the list to the previous page, moving the location
cursor to a new item. This action also selects the new item,
deselects any current selection, and calls the
XmNbrowseSelectionCallback callbacks. If the ComboBox is not
a drop-down type, then this action does nothing.
CBListAction(ListNextPage):
Scrolls the list to the next page, moving the location cursor
to a new item. This action also selects the new item,
deselects any current selection, and calls the
XmNbrowseSelectionCallback callbacks. If the ComboBox is not
a drop-down type, then this action does nothing.
CBListAction(Up):
Moves the location cursor to the previous item in the list.
This action also selects the previous item, deselects any
current selection, and calls the XmNbrowseSelectionCallback
callbacks. Note that, unlike the List ListPrevItem action,
this action wraps around.
CBListAction(Down):
Moves the location cursor to the next item in the list. This
action also selects the next item, deselects any current
selection, and calls the XmNbrowseSelectionCallback
callbacks. Note that, unlike the List ListNextItem action,
this action wraps around.
Virtual Bindings
The bindings for virtual keys are vendor specific. For information
about bindings for virtual buttons and keys, see VirtualBindings(3).
ERRORS/WARNINGS
The toolkit will display a warning if the application tries to set the
value of XmNlist or the XmNtextField resource, which are read-only
(marked G in the resource table).
RELATED
Composite(3), Core(3), XmCreateComboBox(3), XmList(3), XmManager(3),
and XmTextField(3).
XmComboBox(library call)