Why can't I draw straight lines with my tablet pen?

[GIMPsuit]

No, I'm not talking about my hand technique.   

I'm referring to the straight line feature achieved with Shift+LeftClick. The feature works just fine with my mouse. With my tablet pen, however, the dragged line appears when you press Shift, and after "clicking" (pressing the pen to the tablet), the dragged line goes away (as expected) but no line is drawn.

Otherwise, the pen works okay. Even pressure works. Does anyone have a clue?

Edit: video: https://i.imgur.com/lv40OWB.gif

Specs
Arch Linux
GIMP 2.10.20
Monoprice 10594 tablet

[Ofnuts]

The screen shot is not from Gimp 2.10... Does the same paintbrush tool work normally when you are not drawing straight lines?

[GIMPsuit]

(09-09-2020, 07:45 PM)Ofnuts Wrote: The screen shot is not fro Gimp 2.10... Does the same paintbrush tool work normally when you are not drawing straight lines?

That isn't my screenshot; it's from the tutorial site I linked for clarification purposes.

Yes, the same paintbrush works perfectly when not drawing straight lines. I can draw freely with the pen, just not straight lines.

[rich2005]

Should work. This with my old Wacom tablet / Gimp 2.10.20 / kubuntu 18.04

I set up one of the stylus buttons as shift, but I think using the keyboard shift is acutually easier, or maybe just my lack of
practice.

https://i.imgur.com/g18Ou8C.mp4

It is just a tap on the tablet, hold 'shift' down, hover and move to the other end point and another tap on the tablet surface.

Otherwise no idea why the monoprice is not 'seeing the shift' key

[GIMPsuit]

(09-09-2020, 08:43 PM)rich2005 Wrote: no idea why the monoprice is not 'seeing the shift' key

I use the shift on the keyboard. I know that it must "see" the shift key, because that's what makes the dragged line appear. It also registers the "click", but it doesn't make my line.

I made a demo gif just like yours. "Core Pointer" is the mouse.
https://i.imgur.com/lv40OWB.gif