Ctrl + Shift + A
Ctrl + Shift + A
It takes a while to figure out how selections in Gimp work.
It whenever you select you have created a mask and when you combine it with layers it can get very confusing.
If you accidentally select a small bit you cannot edit anything else. I think that is what OP is referring to.
There is a tool that shows you what you have selected that can help.
IMO Gimp isn’t very well documented so you can get stuck for a while before you understand what is going on.
It’s a common scenario in software. We think some things like ui designs and workflows are “natural”, but they’re quire arbitrary, and people just got used to them. Then people who are used to it will feel lost with any different workflow, and people who first learned the different ones may feel at home.
A nice example is the windows ui, that a lot of people who grew up to it feel like the most straightforward way to use a computer, but people who grew up with smartphones usually struggle with it ad find something like the gnome ui more straightforward.