Fix GL viewports under -graphicssystem raster.

GL widgets and native controls have paintonscreen set and bypasses
backingstore. They can thus not rely on the windowsurface flushing
but must be repainted via normal means
(cherry picked from commit ac99b3e243b331d26815b80aab97cdaf0ed06b0f)

1 files changed, 3 insertions, 2 deletions

diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index 653ca8e..2482fb3 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -522,8 +522,9 @@ extern "C" {
     if (QApplicationPrivate::graphicsSystem() != 0) {
         if (QWidgetBackingStore *bs = qwidgetprivate->maybeBackingStore()) {
             // Drawing is handled on the window level
-            // See qcocoasharedwindowmethods_mac_p.
-            return;
+            // See qcocoasharedwindowmethods_mac_p.h
+            if (!qwidget->testAttribute(Qt::WA_PaintOnScreen))
+                return;
         }
     }
     CGContextRef cg = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];