Hi, there has been this bug that has been confusing me for years with the MATE Desktop and I am wondering if it will ever be fixed. If a window has client-side decorations and saves its position when closed, maximizing, closing, then re-opening the window and restoring it will cause it to create dummy window decorations. I filed a bug on it a year ago here and now I'm kind of convinced that it will just never be addressed because it wasn't featured in the 19.10 paper cut release and it's still present in the 20.04 daily builds.
Here is a visual example:
Bug report: https://ubuntu-mate.community/t/when-will-this-window-decoration-bug-be-fixed/