Ensure Composer set to zoomFull() when shown from menu or manager

- Zoom full happens on initial showing or showing after hiding, via user close or spontaneously by os
- If Composer is open, behind other windows or minimized, zoom state is maintained

src/app/composer/qgscomposer.cpp

@@ -445,10 +445,15 @@ void QgsComposer::open( void )
 
 void QgsComposer::activate()
 {
+  bool shown = isVisible();
   show();
   raise();
   setWindowState( windowState() & ~Qt::WindowMinimized );
   activateWindow();
+  if ( !shown )
+  {
+    on_mActionZoomAll_triggered();
+  }
 }
 
 #ifdef Q_WS_MAC

src/app/composer/qgscomposermanager.cpp

@@ -172,11 +172,16 @@ void QgsComposerManager::show_clicked()
       c = it.value();
       if ( c )
       {
+        bool shown = isVisible();
         c->show();
         c->activate();
         c->stackUnder( this );
         raise();
         activateWindow();
+        if ( !shown )
+        {
+          c->on_mActionZoomAll_triggered();
+        }
       }
     }
   }