You cannot use C+[NUM] shortcuts when creative menu is open. This leads to a confusing player experience when they try to save their assigned hotbar while the menu is open.
MC-256340
Cannot use c+NUM to assign saved hotbar while creative menu is open
Open
7
(Unassigned)
Confirmed
Platform
Low
Inventory, UI
1.19.2, 23w06a, 1.19.4, 1.20 Pre-release 1, 1.20 Release Candidate 1, 1.20
Retrieved
(this is what I think happens) The code for c+NUM is probably similar to WASD, keys so the game acts like that as if you press W. (Sorry for the bad grammar)