Comment 3 for bug 1126221

I see the same problem on Trusty 14.04.1 LTS.
I have a VGA monitor on the left, and an HDMI monitor on the right, and a laptop screen that is turned off since I can't seem to run 3 displays at once. The HDMI goes to sleep after 2 hours of inactivity.

It doesn't happen every time, but after several of these sleep cycles, a window like psensor or Totem will often disappear as described.

xrandr snippets:

Screen 0: minimum 320 x 200, current 3600 x 1108, maximum 32767 x 32767
LVDS1 connected (normal left inverted right x axis y axis)
VGA1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 520mm x 290mm
HDMI1 connected 1680x1050+1920+58 (normal left inverted right x axis y axis) 1060mm x 626mm