It would be nice, to be able to switch the
visibility/activity of buttons within a panel on and off.
For example because a certain funtionality in the game is not available yet.
This could be also managed by altering the bitmaps(s) of the button, like
switching it grey.

some thing like

panel_x.button_1=on;
panel_x.button_1=off;

switching the first button of the panel on/off

Yeah, it would be useful, but like you said I guess you could just change the bitmaps and disable the effect of any on_click event.

Yeah this would be really great, especially if you want to make some "tick"-boxes. Therefore you should be able to change the bitmap of a button.

on_click can be deactivate by placeing a black panel over its white a higher layer white overlay