anchors and snap-to
 

Just getting started and these are the things that stick out first:

Why is there no Layout\Anchors for anything but the top level form? It seems the snap-to logic may try to anchor them, but it really needs to be part of the designer to easily set these things.

Speaking of the snap-to, the automatic blue-line snap-tos are nice, but make dragging stuff around very annoying. This should be something that can be turned on by holding down a modifier, like the shift or control key while dragging.

Also, since you use CPPB (I've been a Delphi developer for about 8 years), you are probably familiar with the "Align To" menu options and tool pallete. I think this would be useful here, too.

Looking good so far!

You can hold down ALT while moving to stop the snap lines.

More stuff will be added over time to improve the editing experience, I am currently messing with the editor font and colouring to make it more customisable. Also, all the WoW API will be syntax highlighted next update. Anchors are defined in the skin files and I have made the default pretty simple to start with, complicated resizeable frames with components moving to fit aren't a big priority for me just now. Next update will allow you to add skin files, and I will include the default one as a template so you can go nuts. To be honest, I am not really that much of a WoW UI developer, so I hope for a lot of help from the more advanced members of that community to create components that simplify development of neat UI elements such as tabbed panels, dropdown/context menus, etc. I will be endeavoring to provide design side support for whatever needs they have.