The first time I use the KDE menu editor I was missing the close and save button, The same as in all other KDE programs.
There is a save disk on the top, but I must look very good to see that thing the first time. I think that a close and save button is more integrated and logic in the KDE desktop.
So a simple idea, and simple to integrate (I think), to make it more easy to use.
It’s just an idea… so, if it’s a bad idea…be gentle ;-)