Reproducible recursive repaint crash/assertion

[Vincent van Ravesteijn]

1. New file
2. Split View in Left and Right half
3. Help->Introduction (or open any other file that is larger than the height

of the screen)

4. Scroll down to the bottom
5. Insert Math on the last row
6. See the two math-toolbars appear on the bottom and cover part of the buffer
7. Scroll to the bottom again (this is essential!)
8. Make sure the cursor is still inside the math
9. Click in the document in the left view

LyX exits with the message:
QPaintEngine::setSystemClip: Should not be changed while engine is active
QPaintEngine::setSystemClip: Should not be changed while engine is active
QWidgetPrivate::beginSharedPainter: Painter is already active
QWidget::repaint: Recursive repaint detected

C:/Users/Vincent/OpenSource/LyX/svn-trunk/lib/doc/Intro.lyx.emergency

And in debug mode:
ASSERT: "sharedPainter ? sharedPainter->isActive() : true" in file
kernel\qwidget.cpp, line 4565

[ps@…]

possibly related to #5499

[Juergen Spitzmueller]

Unless someone comes up with a straightforward patch, we'll postpone this to
1.6.3. We need to get out 1.6.2 eventually.

[Vincent van Ravesteijn]

It's a qt-bug. It can be solved by the patch that can be found here:

​http://websvn.kde.org/trunk/qt-copy/patches/0256-fix-recursive-backingstore-
sync-crash.diff?view=markup&pathrev=880178.

It should also be fixed in qt4.5.

[Vincent van Ravesteijn]

* #5821 has been marked as a duplicate of this bug. *

[Uwe Stöhr]

Fixed by Qt 4.5.0, please test.

[Juergen Spitzmueller]

QT bug -- a LyX milestone does not make sense.

[Vincent van Ravesteijn]

Indeed fixed in QT4.5.

[Vincent van Ravesteijn]

* #5862 has been marked as a duplicate of this bug. *