How to Draw the Screen only when Requested in Unity?

I need a Data Editor for my game made with Unity, and initially I started with Qt as it's cross-Platform, but didn't like its Licensing Model. I learnt that one can run a Particular Scene using Command Line arguments and now

I've decided to use Unity for making the Editor which is mostly going to be UI Elements and UGUI System would be perfect.

But I only want to draw the Screen When user Moves a Mouse button, or clicks something. Otherwise I don't want to clear the Screen. Is there a way to do it, other than using the Camera's Don't clear?