Reference and Build Questions

Question

I have a solution with two projects; a main project (windows forms) and a .dll project that contains custom controls that I want to use in the main project.

I complied both projects and added a reference to the dll project in the main project.  Last week the controls I built showed up in the toolbox and now do not.  I have since deleted that project and recreated a new dll project and repeated all steps to add the reference, yet no controls show up in the toolbox.

Any suggestions?

Thanks