Ubuntu how to disable per-application window decoration?

Question

ubuntu

/home is mounted on a separate drive. Initially, there was Kubuntu where it was possible to set special design parameters for it by clicking on the title of any window. Later, Linux Mint (Mate) was installed and there is no window customization option out of the box, but Mozilla Thunderbird is still displayed without a border (as it was specified in Kubuntu). I tried to find and remove all the old settings of compiz, thunderbird, etc. but no result.