&gt; Client side decorations give way more space to the actual content than to waste space for an almost empty titlebar. It allows to combine the titlebar with content from the application itself. You regard them entirely off as a &quot;sin&quot;. Very strong language but you don&#x27;t explain _at all_!<p>You can do that without client side decorations.<p>KDE with Qt even plans to allow telling the Window manager to render specific widgets in the toolbar.<p>The manager can ignore that, and render them as separate toolbar – or even render them in a bar at the top of the screen.