What is the reason why you want to place those panels in one form and not creating 3 different forms? Is it you want to reuse the method, function and properties of form you've created and you don't want to repeat this codes in other form plus they have the same look and feel with some slight differences in Pane1, Panel 2 and Panel3. If your answer is YES you should go to inherited form.
NOTE: Methods and Properties of Parent Form are visible to inherited Form (Only Public and Protected access modifiers).
Create a base class Shape that contains width,height,x, and y. Inherit your shapes from the base class and each shape should know how to paint or draw themselves.
Create another class such as handle or nodes that is assigned to your shapes. This class will resize your shapes while dragging the handles