[PyQt] setting Popup windowFlag causes system to become unresponsive

[Hans-Peter Jansen]

On Friday 27 November 2009, 19:34:31 Jugdish wrote:
> For some reason if I set the windowFlag "Popup" on a QListWidget, the
> widget takes modal focus and it is impossible to give focus back to any
> widget. In fact, my entire system becomes unresponsive. Only the
> QListWidget responds to input, and I have no way of killing the process.
> Here is a very stripped down example of this problem:
>
> ##############################
> from PyQt4 import QtCore, QtGui
>
> app = QtGui.QApplication([])
>
> w = QtGui.QListWidget()
> w.setWindowFlags(QtCore.Qt.Popup)
> w.addItems(["foo","bar","baz"])
>
> button = QtGui.QPushButton("Click Me")
> QtCore.QObject.connect(button, QtCore.SIGNAL("clicked()"), w.show)
> button.show()
>
> app.exec_()
> ##############################
>
> When I run this bit of code and click on the button, a QListWidget pops
> up on top of everything. I can select each of the 3 items in the list as
> expected, but if I click anywhere outside the QListWidget, nothing
> responds, not even if I try to click on items in the taskbar or the
> windows for other running apps! It has something to do with it being a
> QListWidget, because if I change it to just a QWidget, I can click
> outside of it and things still respond.
>
> Am I doing something wrong or is this a bug?

Same here. Almost certainly, this is a Qt bug. Please file a bug report. You 
should be able to workaround this behavior by subclassing QListWidget() and 
adding custom event handler. You will want to do that anyway, since the 
QListWidget appearing in the top left corner isn't that useful either. 

> Here are my system specs:
> GNU/Linux x86_64, Fedora release 8 (Werewolf)
> PyQt 4.5.4

openSUSE i585, sip 4.9.3, PyQt 4.6.2, Qt 4.5.3

Pete