Creating UserControls in Visual Basic NET

Hello.
I have a problem concerning the development / creation of custom usercontrols.

I created a class for a custom scrollbar, using usercontrol and so on... no prob.

It works fine on the main form, I can display it, hide it, change it. I can click on it and move it. No prob.
So far so good.

When I add it to e.g. a panel or a tab or something else, I can display it, I can hide it. But I cannot click on it. It does not react. I can put it in the front with bringtofront, it works. But the events - they dont work. Why?

Please can somebody help me...