Middle click on Intuos3 pen just stopped working

Hello there,

I have a Wacom Intuos3 A5 wide with a pen. I was working in Krita and had the lower button of the pen set to click > middle click. This works as a panning feature in Krita and it just worked a couple of hours ago, but now it suddenly doesn't.

• The middle click on my mouse still works in Krita, so it's not Krita
• I also tried it in Paint 3D where it also worked before, but it also stopped working there.
• I have the latest possible drivers (2016)
• If I assign a different action to the button on the pen, like a regular left click, it does work.
• I also tried unplugging and plugging it back in again.
• And I've restarted my PC.

So only middle click doesn't work, only when I use the pen. Everything else works. This is driving me mad.

How can I fix this?

Thanks in advance for any help.

Edit: I'm running Windows 10