How to remain in FastDraw mode while using FastDraw, a plugin of JOSM

How to stay in the FastDraw mode when a way finished drawing like Building_tools, mean user can stay in this mode for starting drawing another polygon or line segments withour have to enter this mode again by click on its icon or press Shift+F, unless to choosed to leave leave by entering other mode manually?

Is it a option to set? Or I need to modify the source code? How to compile and run after I modified including testing? Thanks.