Looks quite nice.
I like how you've done runtime instead of scantime but overall that does look quite nice and useful for some users.
Nice layout. I'm creating something similar to this to help with the redundancy. Will probably post it once it's done.
If you are going for a full designer/editor I'd say add stuff like:
- Toolbox with all controls, similar to Visual Studio's
- Property grid to easily edit the selected control.
- Snap-to grid to easily align objects.
- Snap-to controls, to align controls similar to how Visual Studio does for C# / WPF.