Application crash in connection with Qt::StaticContents and Qt::WA_StaticContents

If a Q3Table is used in a dialog, it crashes, when changing the windowflags of its parent window. However this doesn't happen, if Qt::StaticContents and Qt::WA_StaticContents are turned off for all widget children of the Q3Table.
Attached is a small example demonstrating this issue:

1. run the application
2. click on the button 'open dialog', a dialog window appears
3. click on the button 'set window flags', the flags of the parent window will be reset
4. close dialog, program crashes

If you run this example with the workaround uncommented (lines 29-35), the application doesn't crash.