PyQt4: Window shows up at another position after hide() and show()

Question

Using PyQt4, when I hide a window and show it afterwards, it appears at another position (at least here on Linux). Example code:

#!/usr/bin/python3

from PyQt4.QtGui import *

app = QApplication([])
widget = QWidget()
widget.setLayout(QVBoxLayout())
label = QLabel()
widget.layout().addWidget(label)

def hideShow():
    widget.hide()
    widget.show()

widget.layout().addWidget(QPushButton('Hide/Show', clicked = hideShow))
widget.show()
app.exec_()

The window disappears and appears, but a bit below and to the right of the original position. I think it's displaced by the size of the window manager's frame around the actual widget.

How can I place the window at the exact position where it was? And why does it move at all? Shouldn't it stay where it is?

Answer 1

On Linux, window placement can be very unpredictable. See this section in the Qt documentation for a break-down of the issues.

There's probably no general solution to the problem, but for me, setting the geometry before the initial show() seems to work:

...
widget.setGeometry(200, 200, 100, 50)
widget.show()
app.exec_()

UPDATE

After some testing with the KDE window manager, I may have discovered a potential solution.

It seems that calling show() immediately after hide() does not give the window manager enough time to calculate the correct window position. So a simple workaround is to explicitly set the geometry after a small delay:

from PyQt4.QtGui import *
from PyQt4.QtCore import QTimer

app = QApplication([])
widget = QWidget()
widget.setLayout(QVBoxLayout())
label = QLabel()
widget.layout().addWidget(label)

def hideShow():
    widget.hide()
    QTimer.singleShot(25, showWidget)

def showWidget():
    widget.setGeometry(widget.geometry())
    widget.show()

widget.layout().addWidget(QPushButton('Hide/Show', clicked = hideShow))
widget.show()
app.exec_()

This works for me using KDE-4.8 and OpenBox, but of course YMMV.