You are referring to AX = 5 for press and AX = 6 for release

If you want the mouse click confirmed then store the values of AX = 5 for the positions and wait for a release monitoring AX = 6. Fairly straight forward for the boundaries you set.

I see no real need for functions like _Hidemouse, etc. But a good function for a click press - release area may be useful. It would save some coding.
Absolute and Interrupt routines can use AX, BX, CX, DX pretty simply already.

I STILL don't see the value of a mouse in Nibbles however! If you can't use arrow keys then tooooooooo bad. You are probably just too old anyhow......

Ted