Can somebody help me telling how to disable this right click menu and application icon on the top left of the title bar? I have looked in tweaks and settings. And I am pretty sure that no extension is also responsible for that, as I tried disabling extensions. I also installed a fresh copy on virtual machine and none of these application icon or menu icon appeared there. And as you're seeing in the screenshot some applications (which are based on GTK2 may be) have the 3 dot menu button and some have the app icon (which is not clickable).