tdf#160971 vcl a11y: Make combobox text selection mode style-able

When selecting an entry of an editable combobox,
the whole text of the text entry currently gets
selected.

That matches the behavior observed with a sample
Windows Forms application.

However, both native GTK and Qt applications
behave differently and do not select the combobox
entry text (s. tdf#160971 comment 11 and the
referenced sample programs and screencasts).

The extra text (un)selection makes the Orca
screen reader on Linux announce an extra
"selection deleted" every time
another entry is selected using the up/down keys
e.g. in the font selection combobox in Writer's
Formatting toolbar when using the qt6 VCL plugin
and the combobox popup is not shown.

Introduce a new style setting to define the
text selection behavior when switching between
entries in a ComboBox and take that
into account in `ComboBox::ImplSelectHdl`.

The default behaviour remains unchanged.

Behavior for the Qt and GTK based VCL plugins
will be aligned more with the behavior of corresponding
native widgets in separate upcoming commits.

Change-Id: Ia2c77245049d708885cbd374c20ce1892259329b
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/168102
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/vcl/settings.hxx b/include/vcl/settings.hxx
index e21091385bc7..7c2fcc633b77 100644
--- a/include/vcl/settings.hxx
+++ b/include/vcl/settings.hxx
@@ -205,6 +205,13 @@ enum class ToolbarIconSize
     Size32       = 3,
 };
 
+/** Text selection behavior when selecting an entry in an editable combobox. */
+enum class ComboBoxTextSelectionMode
+{
+    SelectText, // select the whole text of the new entry
+    CursorToEnd // don't select text, put text cursor to end of text
+};
+
 #define STYLE_CURSOR_NOBLINKTIME    SAL_MAX_UINT64
 
 class VCL_DLLPUBLIC StyleSettings
@@ -627,6 +634,9 @@ public:
     // the default LineWidth for ListBox UI previews (LineStyle, LineDash, LineStartEnd). Default is 1.
     static sal_uInt16               GetListBoxPreviewDefaultLineWidth();
 
+    void SetComboBoxTextSelectionMode(ComboBoxTextSelectionMode eMode);
+    ComboBoxTextSelectionMode GetComboBoxTextSelectionMode() const;
+
     // defines if previews which contain potentially transparent objects (e.g. the dash/line/LineStartEnd previews and others)
     // use the default transparent visualization background (checkered background) as it has got standard in graphic programs nowadays
     void                            SetPreviewUsesCheckeredBackground(bool bNew);