When you drag an object with the RMB (Rigth Mouse Button) into an other object, automatically a pop-up appears, asking if you want to powerclip it [2]
Select it and it will be clipped [3].
Double click the powerclip with the LMB (Left Mouse Button) while holding down the Control key and the clipped object will become editable; you can reposition and / or resize it [4].
Click with the LMB outside of the powerclip while pressing the Control key and the edited powerclip will become of effect.