QMacStyle - change the arrow type only for 'OnlyOneTab' option

It appears the hack was not needed when we have several
tabs (popup button works as expected). Otherwise, this button
suddenly has a different size: it's bigger when selected and
smaller if not (and the holes clipped under the tab shape are
becoming quite visible in the dark mode to the left and right
of a tabbar). For the single tab we need some adjustment in
the size not to have visible difference between inactive/selected
tab.

Fixes: QTBUG-83216
Change-Id: I52511e610ae7b36f261e0218b7e432e747bc9491
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 8 insertions, 2 deletions

diff --git a/src/plugins/styles/mac/qmacstyle_mac.mm b/src/plugins/styles/mac/qmacstyle_mac.mm
index 8e4aaa19c7..84233d6521 100644
--- a/src/plugins/styles/mac/qmacstyle_mac.mm
+++ b/src/plugins/styles/mac/qmacstyle_mac.mm
@@ -3977,13 +3977,19 @@ void QMacStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPainter
                 // which makes no sense on tabs.
                 NSPopUpArrowPosition oldPosition = NSPopUpArrowAtCenter;
                 NSPopUpButtonCell *pbCell = nil;
-                if (isPopupButton) {
+                auto rAdjusted = r;
+                if (isPopupButton && tp == QStyleOptionTab::OnlyOneTab) {
                     pbCell = static_cast<NSPopUpButtonCell *>(pb.cell);
                     oldPosition = pbCell.arrowPosition;
                     pbCell.arrowPosition = NSPopUpNoArrow;
+                    if (pb.state == NSOffState) {
+                        // NSPopUpButton in this state is smaller.
+                        rAdjusted.origin.x -= 3;
+                        rAdjusted.size.width += 6;
+                    }
                 }
 
-                [pb.cell drawBezelWithFrame:r inView:pb.superview];
+                [pb.cell drawBezelWithFrame:rAdjusted inView:pb.superview];
 
                 if (pbCell) // Restore, we may reuse it for a ComboBox.
                     pbCell.arrowPosition = oldPosition;