Tool change not recognized when using XP-Pen tablet+keyboard

Hello everyone. Here is my problem: recently I have bought a tablet, namely XP-pen Deco Pro M, which has 8 buttons on it. But I`m used to use laptop`s keyboard for shortcuts. So when I`m drawing using stylus, and I need to change the brush to the eraser, the first stroke, or even two after changing is not recognized. The same is when I need to switch to BRUSH tool and start drawing - 1st stroke is not recognized. The same is for such tools as eg Lasso (L) , Zoom and Hand (h) - when I press L / H / B (for brush) / E for eraser on the keyboard and start pressing the pen in order to perfrom the stroke or to move across the working surface or to select something - i wont gonna work, no matter how hard I press. If I make the same on the 2nd attemp, everything is Ok. Also if I work only with keyboard+mouse  - everything works. If I use tablet`s buttons to change the tools - againg, everything works fine. So problem is only when using keyboard+pen.

I also tryied Krita / SAI / MediBang - such problem exists only photoshop, on different versions. I prefer SC6 one, but this bug appears in all versions up to 2020.

OS - Win 8.1