How to 'contain' other controls inside my usercontrolscr ?

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C#

I made an empty usercontrolSCR. In it i added a scrollbar + code for mouse wheel to move the scroll and all is working well. But in Form 1, when I add a large textbox in this usercontrolSCR, it does not auto hide the textbox if I move the textbox outside the border of the usercontrolSCR. Like a Panel does it.
What is the code (if it is one), to 'contain' other controls inside this usercontrolSCR ?
Thank you.

What I have tried:

edited>>>
I am talking in designView, not in code.
In code, i make this:
userControlPanel1.Controls.Add(tb1);
tb1.Location = new Point(0, usercontrolSCR.Height - 30);//to test it
and is doing the thing i want.