Refs #8984. Set current win. of MdiArea to current win. of app.

Code/Mantid/MantidPlot/src/ApplicationWindow.cpp

@@ -8797,13 +8797,21 @@ void ApplicationWindow::setActiveWindow(MdiSubWindow* w)
   {
     d_active_window = NULL;
   }
-  else if ( d_active_window->getFloatingWindow() )
+  else
   {
-    // If floating window is activated, we set MdiArea to not have any active sub-window. This makes
-    // sure that we don't have two versions of current active window (d_active_window and active
-    // window of MdiArea) and they are either equal (when docked window is active> or the latter one
-    // is NULL (when floating window is active).
-    d_workspace->setActiveSubWindow(NULL);
+    // This make sure that we don't have two versions of current active window (d_active_window and
+    // active window of MdiArea) and they are either equal (when docked window is active> or the
+    // latter one is NULL (when floating window is active).
+    if ( d_active_window->getFloatingWindow() )
+    {
+      // If floating window is activated, we set MdiArea to not have any active sub-window.
+      d_workspace->setActiveSubWindow(NULL);
+    }
+    else if ( QMdiSubWindow* w = d_active_window->getDockedWindow() )
+    {
+      // If docked window activated, activate it in MdiArea as well.
+      d_workspace->setActiveSubWindow(w);
+    }
   }
 }