Visual Studio 2010 toolbox controls disabled or inactive

Question

I am trying to fix this from last two 2 or 3 days but failed. VS 2010 toolbox in asp application development(design mode or source) is not showing all controls(showing html

Answer 1

This was driving me crazy for a pair of days. In the choose items menu my 3rd party controls (CrystalReportsViewer) were checked. Reset toolbox did nothing to enable them. My solution was changing the target framework from .NET Framework 4 Client Profile to the full version .NET Framework 4, seems the client profile which is a subset of the version optimized for client applications does not support my controls or just using references to other 3rd party .dll librarys. This issue should only be for .NET 3.5 and 4.0, Client Profile is discontinued for .NET 4.5