Following up on the other thread
https://forums.mirc.com/ubbthreads....bug-and-missing-documentation#Post270601

With the addition of bitmasks 64 128 256, it's now possible to check if the right-of-pair is pressed for shift,ctrl,alt. And it's possible to check if left-only is pressed, by checking if the historical bitflag is enabled but the new one isn't. but it isn't possible yet to know whether right-only is pressed. For example, with shift keys, there's currently only 3 possible outcomes, 0 or 4 or 4+64=68

$and(mouse.key,4+64):
neither shift is pressed: 0
left-only shift is pressed: 4
right-only shift is pressed: 4+64=68
both left+right shift are pressed: 4+64=68

If new bit masks are added

4096 Left Shift key
8192 Left Ctrl key
16384 Left Alt key

then

$and(mouse.key,4+64+4096):
neither shift is pressed: 0
left-only shift is pressed: 4+4096=4100
right-only shift is pressed: 4+64=68
both left+right shift are pressed: 4+64+4096=4164

... and then it would be possible to identify all 4 conditions