Emulator

Or so I gather.

What's the problem? Describe what went wrong in few words.
Post processing seems to enable the ability to read outside of the used GPU ram. I see strange events from earlier in my computer's history!

What did you expect to happen instead?
The areas to be black like with PP off.

What steps will reproduce the problem?

1. Enable PP (any filter will do)
2. Start a game.
3. Watch the black areas fill with pictures of whatever you were doing at some point in the past.

Dolphin 3.5 and 3.5-367 are old versions of Dolphin that have
known issues and bugs, so don't report issues about them and test the
latest Dolphin version first.
Which versions of Dolphin did you test on?
A lot. Too many to count. I couldn't find the version that introduced this bug, but I remember the 3.5-xxxx series to not have this issue. I can't test further back than 4.0-960-ish. It doesn't compile after that point.

Does using an older version of Dolphin solve your issue? If yes, which
versions of Dolphin used to work?
See above.

What are your PC specifications? (including, but not limited to: Operating
System, CPU and GPU)
Ubuntu 14.04
Some 8 core AMD
GTS 450

Is there any other relevant information? (e.g. logs, screenshots,
configuration files)
I took the liberty of taking a few screens with both windowed (http://i.imgur.com/9RGMEPO.png) and still-windowed-but-maximized (http://i.imgur.com/tNsfcUl.png) mode.
Dolphin webpages can be easily discerned from the first photo, while previous testing (using Melee instead of ToS) can be seen on the sides in photo 2.

Interestingly, checking the "Use Fullscreen" option seems to fix this issue. I checked the widescreen hack JIC; it had to effect.