It seem that your VS is corrupt.
Here is what I found on the MS forums:
· Please try to run devenv /ResetSettings (in command prompt) to eliminate the related potential settings problem.
· Try disabling Add-ins (e.g. “Tools” | “Add-in Manager”) or run “devenv.exe /SafeMode”.This can eliminate the possibility that third party Add-ins or packages are causing problems. (For more detailed VS command line switches information, see:http://msdn2.microsoft.com/en-us/library/xee0c8y7.aspx )
· Try creating a new project. Sometimes corrupted project settings can cause problems. These are project specific.
· If the issue still exists, I recommend you repair your Visual Studio 2005. To do so: Start>>Control Panel>>Uninstall a program>>Choose Microsoft Visual Studio 2005 – ENU>>Uninstall/Change>>Repair/Reinstall.
· If the problem still occurs, I recommend you update your Visual Studio 2005 to Service Pack 1. You can download Service Pack 1 from here: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=5553
· If your OS is Windows Vista, Windows 7, Windows Server 2008 or Windows Server 2008 R2, I recommend you install this update:http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=7524
· Try to create a new user account. This can help isolate user profile corruption related causes.
I hope this will help.
the Telerik team
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