[xmonad] Tiling messed up while external monitor is connected

[Samir Unni]

Hello,

I'm trying to use an external monitor with my Arch Linux x64/Xmonad 
setup (Intel integrated graphics), and I'm having some tiling issues 
when using the default tiling algorithm. My laptop has a 1440x900 
monitor, to which I've connected a 1280x1024 external monitor in the 
past without any problems. There are also no problems when no external 
monitors are connected.

But when a 1600x1200 external monitor is connected, the tiling on the 
_laptop monitor_ is messed up (go to http://ompldr.org/vOHQ3Mw for a 
screenshot). It may be a little difficult to observe - the window 
heights are reduced to ~10 pixels each and placed at the top of the 
screen. If I open a second window, each one takes up half of the monitor 
width, as usual (the window heights remain at ~10 pixels each). I have 
dzen2 bars at the top and bottom of the laptop monitor and have 
avoidStruts enabled, so the windows shouldn't even be in that particular 
part of the screen.

Any ideas?

Thanks,

Samir Unni