categorise custom workspaces

after creating a custom workspace it's not possible to add it to an existing or new category in the workspace dropdown menu which is accessed by clicking the plus icon at the end of the row of workspaces. Custom workspaces appear in the general category but can't be moved.

I think in that dropdown menu it should be possible to right click a category and choose 'add current workspace to this category', or at the bottom of the dropdown menu an option to create a new category.

It would also make sense to be able to change which sub menu a workspace is in by dragging it to another.