In the desktop client, it could be useful to have an option to hide the menu bar by default (Signal desktop has this, also an Electron-based app), since it's not used that much in day-to-day usage. It could appear when pressing alt (Signal does this, as well as Firefox). Ideally I'd like the application to be more in-line with Gnome design, using a headerbar, but I realize this would be larger thing, and may not be desirable in a third-party application…