My Qt is 4.5.1. When I run my program. It's been assert.

The log as following.
ASSERT: "!tlw->d_func()->extra->topextra->inTopLevelResize" in file painting\qbackingstore.cpp, line 598
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

Any help will be appreciated.