> For three - the dialog layout. If your dialogs have text that's longer than 3-4 words, the chances are that it will either overflow, underflow or wrap differently under different DPIs. This in turn means that you need to test dialog appearance with at least 4 different font sizes and Tahoma 8px for Windows XP. Do you know how hard it is to word a longish sentence so that it would fill about the same space with all 5 combinations? Really damn hard and very time consuming.

I don't understand that one. If the text is going to be a different size because it's scaled with the DPI, then hasnt the dialog itself scaled equally as well?