Custom workflow activity shows up but can't be selected?

Question

I have created a custom workflow activity and successfully deployed it. The issue I am running into is that when I try to select it when creating a workflow using SharePoint designer, nothing happens. It does not get added to the workflow, there are no errors, just nothing. I have been watching the ULS also and nothing is showing up in there either.

Does anyone have any idea why this would happen? Suggestions for where I should start looking?

If there are any parts of the project that will help with this question, let me know and I will post them up.

Answer 1

The most common issues are:

• Make sure the authorizedType entry is in your web.config (for testing you can manually add it or add it using code)
• If this is a new iteration of an existing DLL, you may have to clear your cache on the machine where you are using SharePoint designer.
• Make sure your .actions file is correct.

You might also want to check out Muhimbi's answer on Custom activity created and appearing in Actions list in SPD, but cannot select it.