In boxes where you can adjust properties of an object, there are handles to raise the values. If I click 'to long' on these handles I can't stop them anymore, they continue to give bigger and bigger values.

This is a very strange problem.
I don't have the problem if I lower the values.

Welcome to the forum!

Please tell us your Inkscape version and operating system.  If this is happening in 1.0 beta, we will certainly want to report this as a bug, so developers can fix it.  If it's happening in a lower version, they probably will not try to fix it.

I see you are using a non-English language.  That should not have anything to do with this problem.  However, I have seen reports of some odd behavior with some languages.  So it might help to know which language.

Are you saying that the number in the box just keeps going up, even after you release the mouse button?  It should stop when you release the mouse button. 

Have you noticed any problems with your mouse outside of Inkscape?  Or anywhere else in Inkscape?

Hey Brynn,

Thank you for welcoming me, and for your questions.
As you say, the numbers keep going up, even after I release the mouse button.
I'm using Inkscape 0.92 on a Linux Mint machine. That's the version that is installed 'automatically' by the software manager, apparently.
I have the dutch language version.
I don't have the problem using other software.
As far as my experience reaches now, I don't have the problem elsewhere in Inkscape. E.g. in the 'png export'-panel, (that shows up on the right side of my screen), I can use the handles normally.
I can stop the 'crazy upgoing numbers' by clicking another option in the left panel. E.g. I'm in the select tool when manipulating the numbers, they go crazy, and I click on the zoom-tool and it stops.

I don't know if version 1 is Linux-ready.

Thanks,
Stefan