Actually never heard of this issue, but do you have UAC enabled. If you try disabling it.
That is the only difference I can think about between windows 7 and XP.
There is a doc on MOS which states application designer crashes on windows 7 with UAC enabled, but not showing empty fields and drop downs.
E-AD Windows 7 Crashing Application Designer When Click Grid Properties. [ID 1306881.1]
I tried the solution mentioned for the following issue which is exactly what I am currently experiencing:
E-AD:Missing Grid Property Values On Pagelet In App Designer
The Workstation needs to be installed as the Windows Administrator. One Method to verify if this is the issue is by right clicking on the Application designer Icon and Selecting "Run as Administrator" , then navigation to a grid and viewing the Grid properties USE tab. (Note Values will show.)
This solution too did not work for me.
Do I have to be a local administrator on the machine to use App. Designer 8.51?
Are you still facing the issue?
If you are still facing the issue, please let me know whether it is you laptop/desktop or it is a vmware machine.
Have you installed other versions of PeopleTools before?