Today in the version 0.1 only the BButton, BTextControl, BView and BWindow are supported. The next release will support most of the BControls.
In the actual version, nothing can be saved in a "project file", you have to redraw everything everytime.
My future goal will be to create something like Delphi or C++ Builder... you could compile and code and stay in the BeBuilder IDE.
For the moment the code generation is only C++ but we could imagine to add other languages.... make your choice!