@JonathanBuchh:
Yes, so that is the setting I referred to in my previous comment. And when the base theme is set to dark there is no way the custom theme can be set to light, which is what @liam’s comment suggests to me.
I don’t have a funny cursor, I have a normal one, except that it changes from an arrow to a black bar when it is moved over a dark note spine in Andy mode.
The workaround is to do what I described in my 2nd comment near the top of this page. That works for a while, then it reverts back. I don’t see any other solution.