I just found something very curious:
I dropped a TMemo to show some info, and on it upper rigth corner i try to place a TSpeedbutton to close it. The TMemo is always on top, so the button is not visible and you can not close the tmemo. I try many ways but was impossible: sending tmemo to back, bringing speedbutton to front, using the object inspector...
Then i try with a TButton. It worked as expected, IN FRONT of the Tmemo.
Why the TSpeedButton can not appear in front of a tmemo?