forward showingDesktop signal to effects

effects.cpp

@@ -217,6 +217,8 @@ EffectsHandlerImpl::EffectsHandlerImpl(Compositor *compositor, Scene *scene)
 
     Workspace *ws = Workspace::self();
     VirtualDesktopManager *vds = VirtualDesktopManager::self();
+    connect(ws, &Workspace::showingDesktopChanged,
+            this, &EffectsHandlerImpl::showingDesktopChanged);
     connect(ws, &Workspace::currentDesktopChanged, this,
         [this](int old, Client *c) {
             const int newDesktop = VirtualDesktopManager::self()->current();

libkwineffects/kwineffects.h

@@ -1125,6 +1125,13 @@ Q_SIGNALS:
      * @since 5.0
      **/
     void numberScreensChanged();
+    /**
+     * Signal emitted when the desktop showing ("dashboard") state changed
+     * The desktop is risen to the keepAbove layer, you may want to elevate
+     * windows or such.
+     * @since 5.3
+     **/
+    void showingDesktopChanged(bool);
     /**
      * Signal emitted when a new window has been added to the Workspace.
      * @param w The added window