Comment 3 for bug 947025

This bug also affects me. The suggested workaround works for me. I figured out how to reproduce the bug everytime (at least in my case):

1) Maximize a window to the secondary monitor
2) Unmaximize the window on the secondary monitor.
3) Resize the window so that it is too big to fit in the primary monitor
4) Drag the window to the primary monitor (because it is too big to fit, part of it will be in a different workspace)
5) Maximize the the window

Result: Even though the window is almost entirely in the primary monitor, it maximizes to the secondary monitor.