Windows suddenly treats fullscreen as half of actual screen

Question

Sometimes, after I unlock my computer, the windows are all half the size of the screen and when using the maximize button they do not expand to fill the whole screen. This also affects the Aero Snap feature. I can demonstrate with this screenshot, but it's really the only way to see the actual effect of the problem.

As you can see, I've dragged the window to the right and as soon as it hits about a 1/3 of the way across the screen it thinks that it is at the edge of the screen and it initiates Aero Snap. This is not limited to Aero Snap I disabled Aero Snap and just used the maximize functionality and I still had the same problems. I also restarted the Desktop Window Manager and that also did not fix the problem.

This is on a multi-monitor setup and it was on the external monitor. I disconnected the external monitor and reconnected it, and the problem moved from the external monitor to the default monitor, and then manifested itself on the left side instead of the right side. I tried changing the "Main Monitor" option in screen resolution. I tried changing the screen resolution. None of this solved the problem.

I can always restart, but this is time consuming especially because I'm a developer and I have to have several services running that take a long time to start up. I need to be able to fix this problem without restarting my computer.

Solution

Turns out it was Pidgin. I closed Pidgin and it immediately resolved the issue. I started up Pidgin again and everything was back to normal.

More detail about the Pidgin effect is given in the solution to the following post: Pidgin feature The feature's effect seems to be enforced even if the Buddy List isn't docked to an edge.

Comments

[snowe2010]

I don't use screen savers :( Like none. I don't even use blank screens. It goes to sleep before screen saver turns on.

[snowe2010]

Nope, coworker just told me what the problem actually was. Turns out it was Pidgin. I closed pidgin and it fixed the problem.