Accidental override of eraser tool when using touch pad

Hi,

I recently had an experience which I’d like to share. I’m aware that I might be dumb, but even if that’s the case I think it might be worth looking at.

I am a total noob in drawing, but enjoy using krita on linux on my 2-in-1 lenovo tablet. For the most part, this has been a very nice experience. However, something really weird happened, which took me quite long to figure out. I’ll explain my experience, and then my interpretation of what I think happened.
I feel like Krita worked as designed, and the design actually seems quite nice, but to me it took quite long to figure out, with me attempting some insane fixes on the way.

At some point while using krita to doodle, my eraser stopped working. Like, instead of switching to the eraser (on the pen button) Krita would use one of the pens. I could switch to the eraser by hand, but the button always switched to a pen - the same pen.
I figured (since I’m using cachyOS, and had just received a Krita update) that something minor might have broken about my touch pen somehow. But no matter what settings I changed in Krita, or KDE, it kept doing this thing.
I found a temporary work-around in using the flatpak-version of Krita, which mostly worked fine, but had some minor gripe I don’t currently remember (when compared to the direct install).
I asked a friend of mine for help, who used Krita more often, and she also couldn’t figure out what was going on, and browsing the forums + documentation didn’t yield me a fix either.
In the end, by pure chance I tried to change the selected tool while holding the button, and this switched the tool. I must have accidentally done this wayy before, causing the tool of the alternate button to be switched.

In hindsight, this behavior is kinda logical (switch the ‘alternate tool’ by pressing the tool while holding the button), but it feels totally hidden. This combined with this setting being seemingly very persistent made it very hard for me to discover this feature.

I do not know if more people have faced this before, and also would not really know how you would assist people with this, but I thought it may be a case to look into.

Cheers and thanks for the cool software!
Nander