Add a subclassed Control by code

I’ve startet to develop a class for adding controls dynamically to a view or container with all the constraints to set the controls positions.
If i use the standard Controls everything works fine, but if i use a subclassed control (a canvas to draw a Buttonbar in this case) the control isn’t shown (Paint event not fired).

If i drag the subclassed control into a view everything works fine, adding by code fails.

Please give me a hint how to solve this, because my knowledge about this is still not deep enough.
Thanks in advance