So I had a peek in Prefs.ini:
It seems a little excessive and indeed perhaps one of the reasons why the display stops working when click-panning is that too much texture is being crammed in at once.
Additionally, I had a peek in debug.err and it reports:
Display Memory: 2809 MB
This is for an AMD Radeon HD 5570 which only had 1GB of memory so... maybe a problem there?