3ds Max Custom UI - A quad in a quad does not work properly in 3ds Max

It seems 3ds Max (2020, 2019 and perhaps the lower versions) doesn't like a quad (or quads) in a quad. Does anyone know why is that so? A quad in a quad works perfectly while you are customizing it and after you close the Customize UI dialog but when you close Max and then open it - a new quad with the same label (but not working, just a label) appears next to the one you put previously and Max keeps adding such idle quad labels with the same name with the starting of each new session. Quad(s) in a quad is extremely handy unlike menus where you must turn left or right and scroll up or down and often your mouse escapes the menu and then you have to repeat the movement sometimes two or three times more. You can make the menu flat of course but it often takes much space like this. Does anyone know what's wrong with 3ds Max with this quad(s) in a quad issue and is there a fix for this?