Perhaps this has something to do with my Lenovo's fingerprint login system, but every time that I unlock my computer with my fingerprint, the ALT key appears to be stuck "on".
1. bring up a window that is not maximized
2. lock my system (ctrl + alt + del, enter)
3. swipe my finger across fingerprint reader - this logs me back in
4. left click in the middle of the original window opened in step 1, allowing me to move the window
If I press ALT again, this fixed the problem, so it's not a huge show stopper. I wonder if adding the fingerprint reader process to the blacklist would resolve it.
Hope this is enough info.