The dialog is taken largely unchanged from MW4. I believe it's not very intuitive and uses untypical layout. So I suggest to rework it in the the way similar to raster categories dialog: single grid and buttons to the right of it. Do you agree?
I meant the first one.
I assume you mean this dialog:
There is also a second dialog about categories:
I'm not sure which raster dialog you are referring to but making all the dialogs look similar is always a good idea
I've committed the simplified version of a dialog.