I get a crash when searching with qpackagekit.

apt backend.  pkcon works fine.

ASSERT: "last >= first" in file kernel/qabstractitemmodel.cpp, line 2095


#0  0x00007f8f55a93095 in raise () from /lib/libc.so.6
#1  0x00007f8f55a94af0 in abort () from /lib/libc.so.6
#2  0x00007f8f567c56d5 in qt_message_output () from /usr/lib/libQtCore.so.4
#3  0x00007f8f567c57fd in qFatal () from /usr/lib/libQtCore.so.4
#4  0x00007f8f5686b03e in QAbstractItemModel::beginRemoveRows () from /usr/lib/libQtCore.so.4
#5  0x000000000040f758 in PackageModel::clear (this=0x7184e0) at PackageModel.cpp:82
#6  0x0000000000408885 in MainWindow::doSearch (this=0x7fff5fbaddf0) at MainWindow.cpp:106
#7  0x0000000000410d97 in MainWindow::qt_metacall (this=0x7fff5fbaddf0, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0x7fff5fbad330)
    at moc_MainWindow.cpp:85
#8  0x00007f8f56884a00 in QMetaObject::activate () from /usr/lib/libQtCore.so.4
#9  0x00007f8f57186007 in QAbstractButton::clicked () from /usr/lib/libQtGui.so.4
#10 0x00007f8f56f86a9b in ?? () from /usr/lib/libQtGui.so.4
#11 0x00007f8f56f88155 in ?? () from /usr/lib/libQtGui.so.4
#12 0x00007f8f56f881fb in QAbstractButton::timerEvent () from /usr/lib/libQtGui.so.4
#13 0x00007f8f56883cac in QObject::event () from /usr/lib/libQtCore.so.4
#14 0x00007f8f56d0271f in QWidget::event () from /usr/lib/libQtGui.so.4
#15 0x00007f8f56f87340 in QAbstractButton::event () from /usr/lib/libQtGui.so.4
#16 0x00007f8f57009468 in QPushButton::event () from /usr/lib/libQtGui.so.4
#17 0x00007f8f56cc03eb in QApplicationPrivate::notify_helper () from /usr/lib/libQtGui.so.4
#18 0x00007f8f56cc3d73 in QApplication::notify () from /usr/lib/libQtGui.so.4
#19 0x00007f8f56872ae0 in QCoreApplication::notifyInternal () from /usr/lib/libQtCore.so.4
#20 0x00007f8f568968d6 in ?? () from /usr/lib/libQtCore.so.4
#21 0x00007f8f5689368d in ?? () from /usr/lib/libQtCore.so.4
#22 0x00007f8f54ae43b4 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#23 0x00007f8f54ae76c5 in ?? () from /usr/lib/libglib-2.0.so.0
#24 0x00007f8f54ae7bab in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#25 0x00007f8f56893c1b in QEventDispatcherGlib::processEvents () from /usr/lib/libQtCore.so.4
#26 0x00007f8f56d3625f in ?? () from /usr/lib/libQtGui.so.4
#27 0x00007f8f56871fc8 in QEventLoop::processEvents () from /usr/lib/libQtCore.so.4
#28 0x00007f8f568720e6 in QEventLoop::exec () from /usr/lib/libQtCore.so.4
#29 0x00007f8f56874241 in QCoreApplication::exec () from /usr/lib/libQtCore.so.4
#30 0x00000000004078fb in main (argc=1, argv=0x7fff5fbae0f8) at main.cpp:27