When I try and edit an individual component the sliders on the bottom and right of the screen disappear. To move the image I have to guess where the slider may be and click the mouse there. Very hit and miss.
The circuit layout page functions perfectly.
I assume KiCad is expecting a wheel mouse not a laptop touch pad?
EDIT. I went out and got a wheel mouse - unrelated.
There is logic to it, but probably from a different angle then you’d guess.
Those toolsets are an artifact of the way software development in Open source projects work. It allows the developers to work on big underlying changes (the way all GUI stuff is rendered) and for people to try new features and give feedback before those changes are fully developed. Some people have hardware problems, and they can then also fallback to an older toolset that is better debugged.
It also happens that new features only get implemented for the new toolset and the toolsets diverge in functionality.
That you mention just:
I have there: Modern Toolset (Acellerated) and Modern Toolset (Fallback).
What is your KiCad version? If it’s any older then V5.1.9, then upgrade to that. It may be a bug that has already been fixed.