How to use ArtRage with a tabet? (dialog inputs etc.)

[VanKurt]

Hi there,
I just bought ArtRage for my Yoga C940 (Windows 10 convertible). But I'm having major problems using ArtRage in tablet mode.
Every dialog where I must enter a number must be operated with a keyboard. I don't see any way to change the values with the stylus (e.g. via a slider).

Example: a layer's opacity:


Is there a setting I have missed? Or is ArtRage just not made for touch/stylus input?

For now I always have to pick up my device, flip the screen around (leave tablet mode), enter the number, flip the screen back around (enter tablet mode) and continue drawing. Tis is super-annoying.

PS: Not even the on-screen-keyboard pops up when I set the focus to the input control with my stylus...