I've been experiencing this unfortunate problem ever since I started playing FFXIV again. I play in Windowed mode on Windows 7 SP1 x64. I have two monitors, and play using a keyboard 90% of the time.

Brief description of the glitch:
I'm doing mission/leves/dungeon/etc and go to target a nearby NPC. My targeting system then goes crazy, and rapidly cycles (clockwise mostly, but also counter-clockwise) through all available targets indefinitely and without additional input.

This glitch also causes any keyboard input to be displayed from Right to Left. IE: I type "/shutdown" and it shows up "nwodtuhs/"

What I think may be causing glitch:
When I click into the window with my mouse, (from another active window) and then press tab, it randomly happens. I haven't been able to forcefully make this happen, it's just sporadic. I think it has something to do with the mouse & keyboard interaction to the windowed environment.

What I do to fix this glitch:
1. Mash on my keyboard with both hands flat, concentrating on movement, targeting & camera rotation keys.
2. Mashing on tab/shift/caps lock/ctrl/alt
3. Stop what I'm doing, and shutdown the FFXIV program. Because of the keyboard right to left input, I have to enter "nwodtuhs/" in order to properly shutdown the game. (Very hard to use mouse to manually shut down program)

If anyone knows what's causing this, please feel free to direct me to another thread/forum/topic/etc. I've not tried the full screen, but due to dual monitors I'm sure I would be force closing the game far more often then this error occurs.