QMdiArea: Take scroll bars into account when tiling subwindows

QMdiAreaPrivate::resizeToMinimumTileSize() does not take into account
scroll bars when calculating the minimum size for the QMdiArea widget.
As a result, if scroll bars are enabled or showing during a tiling
operation, the top-level widget incorrectly expands in size (instead of
utilizing the scroll bars). Therefore, we should only resize the
top-level widget if scroll bars are disabled.

Fixes: QTBUG-40821
Change-Id: I3a8b7582d23fdf12d2b09f3740eea6b60bb395c3
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/widgets/widgets/qmdiarea.cpp b/src/widgets/widgets/qmdiarea.cpp
index c1817060dd..cdc1291511 100644
--- a/src/widgets/widgets/qmdiarea.cpp
+++ b/src/widgets/widgets/qmdiarea.cpp
@@ -1296,7 +1296,11 @@ QRect QMdiAreaPrivate::resizeToMinimumTileSize(const QSize &minSubWindowSize, in
             minAreaHeight += 2 * frame;
         }
         const QSize diff = QSize(minAreaWidth, minAreaHeight).expandedTo(q->size()) - q->size();
-        topLevel->resize(topLevel->size() + diff);
+        // Only resize topLevel widget if scroll bars are disabled.
+        if (hbarpolicy == Qt::ScrollBarAlwaysOff)
+            topLevel->resize(topLevel->size().width() + diff.width(), topLevel->size().height());
+        if (vbarpolicy == Qt::ScrollBarAlwaysOff)
+            topLevel->resize(topLevel->size().width(), topLevel->size().height() + diff.height());
     }
 
     QRect domain = viewport->rect();