When using XRandR to switch the resolution of my VGA-connected
external monitor for my laptop, the mouse cursor disappears. The mouse
cursor is still visible on the laptop display.
The problem does not occur with metacity, just with fluxbox. (Though I
should qualify that it used to happen erratically with metacity, and
often switching the VGA off and on again with xrandr made the cursor
re-appear.) It also happens with the KDE4 window manager (though I
haven't confirmed this recently.)
If I switch graphics mode (by switching virtual terminal to VT1 and back
again to VT7), the mouse cursor re-appears.
I've tried xsetroot -cursor_name right_ptr which doesn't make it
re-appear. I've tried switching the VGA output on and off several
times with xrandr.