State scheduling

[metsie2912]

Hi,
I don't know if this is really an issue, but I can't manage to get state scheduling to work. I would love to have dual function keys, like on my Ergodox EZ, where left shift is shift when hold, but when tapped, it's "(". However, I just can't get this to work.
I can reassign left shift like to the following:
U"LSHIFT" : U"LSHIFT"(H), U"9", U"LSHIFT"(R);
Which enters a "(" when pressed, but shift doesn't work anymore.
U"LSHIFT"(UP) : U"LSHIFT"(H), U"9", U"LSHIFT"(R);
or
U"LSHIFT"(UR) : U"LSHIFT"(H), U"9", U"LSHIFT"(R);
Doesn't work, now shift stays shift, also when tapped.
Is this feature just not yet implemented? Or am I using it incorrectly?
Any help with this issue is much appreciated!

[kll]

This is not implemented yet and mentioned already elsewhere in places like #23

[dmgm]

Is this still open after 2 years?
I think the functionality exists in qmk, but there are trade offs.
Is KLL still in active development?