Well, it doesn't seem to be good for anything for the moment.
What should I call the layout area? It does not update properly once MainFrame.wxs is opened, the layout is shown once and then disappears.
I can switch between "layout" and "standard" without problem, but if I try to do something with the symbols att the bottom it starts swapping, and my beachball starts rolling (Windows equivalent would be the hourglass, I guess).
However, If I try to select a "layout" symbol that does not apply, I get what I would think is a proper errer dialog ("This item already has a sizer, cannot add another one").
I was actually able to ad a few buttons to the template layout under the "standard" tab, but I just saw them by chance a few minutes later.
The layout is coming and going, and it is definitely not possble to adjust anything with the mouse. If you drag a corner handle, nothing happens, but next time you get to see the layout, the shape may have changed.
It could be that the functions are working in principle, but the graphics and memory management makes impossible to use. If this problem is Mac specific, I have no idea.