Let's see if this image looks better:
How it works better...
The \00 is the NULL chracter, you have to switch to '\' Coded Display, to get it working.
This is the string you can use to tweak the File Dialog bevaviour.
*.txt;*.doc;*.html)\00*.txt;*.doc;*.html;\00Image\sfiles\s(*.png;*.jpg)\00*.png;*.jpg\00\00
I'm not sure why it works, and if it always will be supported but it's quite good feature.
//Mikael