>One of my targets - besides making this thing works - is to make it close to transparent and requiring no attention. Maybe I'm being overconfident on this, but my goal is to implement a few changes on the framework's base classes and let event binding do the rest.

Shudder. My framework has it's own idea of moving stuff around, in an order not predictable from outside. You would have ZORDER and TABORDER as only order.
So basically, it would need to alter the size according to the DPI
- some stuff may be moved be your tool
- some stuff or it's container needs to be altered by own stuff, because it depends of different problems

AND, what comes to my mind will be not easy to fix: objects of the CONTROL class, where you do not have access to the contained stuff.

Also some UI elements are created on the fly, so you need to watch ADDOBJECT and NEWOBJECT of the containers...