qt-bugs@ issue : N45716

applied: no

author: Enrico Ros <eros.kde@email.it>

QScrollView unwanted repaint fix.

This fixes the 'flashing' konqueror window on activation / deactivation by

saving 1 unwanted repaint (when konqueror window has background).

I tracked down to the problem to the internal QViewportWidget of the

QScrollView class.

When a window is activated the activation event is recursively propagated

to all childs triggering the windowActivationChange() functions in the

widget it passes by.

What happens when the event gets to the Viewport?

At this point the event has already been handled by windowActivationChange()

of the parent widget (a QIconView for example) and has then been propagated

to the Viewport that will handle it with the default

QWidget::windowActivationChange implementation, maybe raising an unwanted

update(); so here we stop the event.

As an addition: if the parent reimplements the windowActivationChange()

function, mainly to block the update, it won't be happy if the child will

trigger the update. If the parent do not reimplement the function il will

inherits the default implementation and there is no need for the viewport's

one.

--- src/widgets/qscrollview.cpp.orig	2004-03-29 10:17:04.000000000 +0000

+++ src/widgets/qscrollview.cpp	2004-03-30 16:40:07.599978320 +0000

@@ -1551,6 +1551,9 @@

         case QEvent::LayoutHint:

             d->autoResizeHint(this);

             break;

+        case QEvent::WindowActivate:

+        case QEvent::WindowDeactivate:

+            return TRUE;

         default:

             break;

         }