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
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
I had the same problem and fixed it now after 3 days:
Right click in toolbox and remove check from "SHOW ALL" (if checked)
I worked for me doing the following steps:
Probably your project is RUNNING. STOP the project then your toolbar items will become enable.
What helped me was changing Project type from Windows Application to Class Library - then (after re-build and reopen...) I got all Controls Enabled.