When we switched to a custom window chrome, we lost many of the native window features from each operating system.
Window chrome refers to the area around a desktop software application that is produced and handled primarily by the operating system. It usually includes the title bar, the close/minimize/maximize buttons, and sometimes a border around the entire window.
Due to these issues and several other issues with the current software theme, we are planning to change the UI again and switch back to native window chrome, at which point many of these native features will be restored. We're very sorry for the trouble.