Filling the windows with some (inter-active) content was the next step. As you can see in the picture, the toolbar at the left now has two buttons. If you click at the right one, the window at the right is opened (a first version of the path building interface).
The sizes and positions of all widget elements are computed automatically, so if you change the text (eg use a different language than English) or if you use different arrow sprites, everything is moved around to fit the new sizes.
Note that the slightly shorter titlebar of the path build window is not a bug. The system thinks an 'X' close button is located there, but since there are no graphics for it yet, you cannot see it :)
Adding paths to the program would be a nice next step perhaps. I don't really like the 'build single path tile with each click' idea, so I am still pondering a better system, in particular for building in the air.
