Add an option to scroll the QComboBox on macOS with the mouse wheel

Since there may be some applications that want to make their comboboxes
scrollable or not with the mouse wheel then a style hint is added to
make this toggable. It defaults to true for all platforms except macOS
to keep it in line with existing behavior.

[ChangeLog][QtWidgets][QStyle] Added SH_ComboBox_AllowWheelScrolling as
a style hint to enable/disable the use of the mouse wheel in a QComboBox.
This defaults to true in all styles except the macOS one so there is no
change in existing behavior.

Task-number: QTBUG-53094
Change-Id: I6eb61e1990bfc79e3b3ea82d7b91ee39096fa077
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 6 insertions, 6 deletions

diff --git a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
index c65cfa3e1a..0c229c9194 100644
--- a/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
+++ b/tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
@@ -2052,13 +2052,13 @@ void tst_QComboBox::mouseWheel_data()
     QTest::newRow("upper locked") << disabled << start << wheel << expected;
 
     wheel = -1;
-#ifdef Q_OS_DARWIN
+    const bool allowsWheelScroll = QApplication::style()->styleHint(QStyle::SH_ComboBox_AllowWheelScrolling);
     // on OS X & iOS mouse wheel shall have no effect on combo box
-    expected = start;
-#else
-    // on other OSes we should jump to next enabled item (no. 5)
-    expected = 5;
-#endif
+    if (!allowsWheelScroll)
+        expected = start;
+    else // on other OSes we should jump to next enabled item (no. 5)
+        expected = 5;
+
     QTest::newRow("jump over") << disabled << start << wheel << expected;
 
     disabled.clear();