QMdiArea + QwtPlot = Crash?

[exdream]

Hi!

I´m using a QMainWindow with a QMdiArea.

When i add a simple QMdiSubWindow (with the line "setAttribute(Qt::WA_DeleteOnClose);" in the constructor) everything works.

But when I add a QwtPlot to this QMdiSubWindow and close this SubWindow my program crashes.

Visual Studio shows me an error somewhere in the file "free.c".

When I delete the line "setAttribute(Qt::WA_DeleteOnClose);" i can close the SubWindow without the crash, but my QMdiArea thinks that there is still an active QMdiSubWindow (logically).

Anybody knows this problem?

UPDATE:
I have the same problem with any Qwt Widget in a QMdiSubWindow.

Thanks and greetings,
André