How to stop Child GUI from being draggable

Hi All

It seems I'm struggling to find a solution here.

I have one Main GUI and 5 Child GUI without borders so it fits nicely within the main GUI.
If I select any of the Child GUI's I am able to move (drag them anywhere within the Main GUI.
I have tried all number of permatations in the CreateGUI ex-styles and GUICtrlSetState but none of the seem to work.
There is probably a very simple explanation and solution and if I had hair I would be pulling out right now.

Is there a way to stop this from being possible?

Many thanks in advance.