ignore Desktops under X11

app/wm/tracker/windows.cpp

@@ -322,7 +322,7 @@ bool Windows::isValidFor(WindowId wid) const
         return false;
     }
 
-    return m_windows[wid].isValid();
+    return m_windows[wid].isValid() && !m_windows[wid].isPlasmaDesktop();
 }
 
 QIcon Windows::iconFor(WindowId wid)

app/wm/xwindowinterface.cpp

@@ -464,7 +464,7 @@ bool XWindowInterface::isValidWindow(const KWindowInfo &winfo) const
         return true;
     }
 
-    constexpr auto types = NET::DockMask | NET::MenuMask | NET::SplashMask | NET::PopupMenuMask | NET::NormalMask | NET::DialogMask;
+    constexpr auto types = NET::DesktopMask | NET::DockMask | NET::MenuMask | NET::SplashMask | NET::PopupMenuMask | NET::NormalMask | NET::DialogMask;
     NET::WindowType winType = winfo.windowType(types);
     const auto winClass = KWindowInfo(winfo.win(), 0, NET::WM2WindowClass).windowClassName();
 
@@ -473,6 +473,11 @@ bool XWindowInterface::isValidWindow(const KWindowInfo &winfo) const
         return false;
     }
 
+    //! reject desktop window
+    if (winType != -1 && (winType & NET::Desktop)) {
+        return false;
+    }
+
     if (winType == -1) {
         // Trying to get more types for verify if the window have any other type
         winType = winfo.windowType(~types & NET::AllTypesMask);