Only show extent of open composer windows

src/app/qgsdecorationlayoutextent.cpp

@@ -25,7 +25,7 @@
 #include "qgsgeometry.h"
 #include "qgscsexception.h"
 #include "qgslinesymbollayer.h"
-
+#include "qgscomposer.h"
 #include "qgisapp.h"
 #include "qgsapplication.h"
 #include "qgslogger.h"
@@ -109,8 +109,10 @@ void QgsDecorationLayoutExtent::render( const QgsMapSettings &mapSettings, QgsRe
   const QgsMapToPixel &m2p = mapSettings.mapToPixel();
   QTransform transform = m2p.transform();
 
-  Q_FOREACH ( QgsComposition *composition, QgsProject::instance()->layoutManager()->compositions() )
+  // only loop through open composers
+  Q_FOREACH ( QgsComposer *composer, QgisApp::instance()->printComposers() )
   {
+    QgsComposition *composition = composer->composition();
     Q_FOREACH ( const QgsComposerMap *map, composition->composerMapItems() )
     {
       QPolygonF extent = map->visibleExtentPolygon();

src/app/qgsdecorationlayoutextent.h

@@ -34,21 +34,28 @@ class APP_EXPORT QgsDecorationLayoutExtent : public QgsDecorationItem
     Q_OBJECT
   public:
 
-    //! Constructor
+    /**
+     * Constructor for QgsDecorationLayoutExtent.
+    */
     QgsDecorationLayoutExtent( QObject *parent = nullptr );
 
+    /**
+     * Returns the fill symbol used for shading layout extents.
+     * \see setSymbol()
+     */
     QgsFillSymbol *symbol() const;
+
+    /**
+     * Sets the fill \a symbol used for shading layout extents. Ownership of
+     * \a symbol is transferred.
+     * \see symbol()
+     */
     void setSymbol( QgsFillSymbol *symbol SIP_TRANSFER );
 
   public slots:
-    //! set values on the gui when a project is read or the gui first loaded
     void projectRead() override;
-    //! save values to the project
     void saveToProject() override;
-
-    //! Show the dialog box
     void run() override;
-    //! render the copyright label
     void render( const QgsMapSettings &mapSettings, QgsRenderContext &context ) override;
 
   private: