I got the same problem.
While researching this issue I discovered:
- Running Dev studio as administrator did not help.
- When creating a new webapplication, property builder works fine.
- When editing a specific webapplication, property builder doesnt save changes.
- When moving the grid (the one metioned in #3) to a different part of the webform, the property builders does work and does save changes.
- Using a different machine and a different user did not have any effect.
From what I have gathered so far, comparing the aspx files between the new webapplication versus the one showing problems should reveal more clues. If I find anything intersting, I'll post them here.
Vista Business SP1
Dev Studio Team System 2008 Version 9.0.30729.1 SP
.NET Framework Version 3.5 SP1
Telerik RadControls for ASP.NET Ajax Version 2008.3.1314.35