Mouse pointer disappears when over line number column?

[Edward Shave]

I just started using notepad++ today. I’m running windows 10.
All seems fine until I move the mouse over the area containing the line numbers at which point the cursor disappears…!
If I keep moving the mouse left the cursor eventually reappears when it hits the left edge of the display.
The invisible area actually starts just as I hit the line connecting the + and - (expand and collapse) thingies.

Did a search but couldn’t find anyone else complaining of this so probably I’ve done something wrong?

[Edward Shave]

Rebooted PC and now it’s working?

All’s well that ends well ;o)