More bugs

As I advance on the task of making the control example work, I keep coming accross new bugs. Now I discover that some controls inside the notebook page, do not update their state correctly, but I'll leave that problem for later.
Right now I'm learning how to capture the mouse events inside the notebook pages. I also fixed a crash produced by right mouse button being clicked inside the notebook window.

My work will slow down a little the next weeks for personal reasons.