> > However, this tells me nothing about an efficient debugging of > > redisplay_internal, and about display in general. > > > > Could you suggest me something efficient, please? > > I usually just use standard GDB breakpoints. Maybe you could be a bit > more specific about what you want to do. > Thanks. For example, suppose that I had 2 frames X and Y. Suppose that Vframe_list = ( X Y Z T ) and selected_frame = X. What would you do for emacs to display (caddr (member (selected-frame) (frame-list) ) ) = Z instead of X? In general, suppose that you want to display a frame different of selected_frame . What should you do? Apart from redisplay_internal, in which functions should modify? Alin.