Original thread: https://en.smath.info/forum/yaf_postst12666findunread_How-to-navigate-fast.aspx
(points 4.1 and 4.3)
possibility for point 4.1 might be to introduce a variable in the code to prioritize some functions (mat(), line(), sys(), cases(), ...) then allow (f.e.) CTRL+ARROWS to navigate to the closer parent argument of functions with suck priority.
point 4.3 - navigate to next empty argumetn might be assigned to UP/DOWN arrows, since TAB and SHIFT+TAB are already assigned