(gdb) bt
#0  0xb6bc3309 in QPainter::worldMatrixEnabled () from /usr/lib/libQtGui.so.4
#1  0xb6b1871c in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#2  0xb6b18622 in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#3  0xb6b18622 in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#4  0xb6b18622 in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#5  0xb6b18622 in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#6  0xb6b18622 in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#7  0xb6b18622 in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#8  0xb6b17be8 in QWidgetPrivate::drawWidget () from /usr/lib/libQtGui.so.4
#9  0xb6b1871c in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#10 0xb6b17be8 in QWidgetPrivate::drawWidget () from /usr/lib/libQtGui.so.4
#11 0xb6b1871c in QWidgetPrivate::paintSiblingsRecursive () from /usr/lib/libQtGui.so.4
#12 0xb6b17be8 in QWidgetPrivate::drawWidget () from /usr/lib/libQtGui.so.4
#13 0xb6c85a5e in ?? () from /usr/lib/libQtGui.so.4
#14 0xb6c85f27 in ?? () from /usr/lib/libQtGui.so.4
#15 0xb6b193d6 in QWidget::event () from /usr/lib/libQtGui.so.4
#16 0xb6e691d7 in QMainWindow::event () from /usr/lib/libQtGui.so.4
#17 0x08110c25 in QgisApp::event ()
#18 0xb6ac179c in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#19 0xb6ac96ea in QApplication::notify () from /usr/lib/libQtGui.so.4
#20 0xb7615123 in QgsApplication::notify () from /usr/lib/libqgis_core.so.1.7.0
#21 0xb73cd191 in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#22 0xb73cde15 in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/libQtCore.so.4
#23 0xb73ce00d in QCoreApplication::sendPostedEvents () from /usr/lib/libQtCore.so.4
#24 0xb73f7a4f in ?? () from /usr/lib/libQtCore.so.4
#25 0xb5c651d8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#26 0xb5c68873 in ?? () from /usr/lib/libglib-2.0.so.0
#27 0x08ccd110 in ?? ()
#28 0x00000000 in ?? ()