Don't open non-modal dialog from a modal symbol selector dialog

Author: nyalldawson

src/app/qgsappwindowmanager.cpp

@@ -1,6 +1,6 @@
 /***************************************************************************
-                             qgswindowmanagerinterface.cpp
-                             -----------------------------
+                             qgsappwindowmanager.cpp
+                             -----------------------
     Date                 : September 2018
     Copyright            : (C) 2018 Nyall Dawson
     Email                : nyall dot dawson at gmail dot com
@@ -59,8 +59,8 @@ QWidget *QgsAppWindowManager::openApplicationDialog( QgsAppWindowManager::Applic
       }
       mLayoutManagerDialog->show();
       mLayoutManagerDialog->activate();
+      return mLayoutManagerDialog;
     }
-    return nullptr;
   }
   return nullptr;
 }

src/app/qgsappwindowmanager.h

@@ -1,6 +1,6 @@
 /***************************************************************************
-                             qgswindowmanagerinterface.h
-                             ---------------------------
+                             qgsappwindowmanager.h
+                             ---------------------
     Date                 : September 2018
     Copyright            : (C) 2018 Nyall Dawson
     Email                : nyall dot dawson at gmail dot com

src/gui/symbology/qgssymbolslistwidget.cpp

@@ -397,8 +397,14 @@ void QgsSymbolsListWidget::updateModelFilters()
 void QgsSymbolsListWidget::openStyleManager()
 {
   // prefer to use global window manager to open the style manager, if possible!
-  // this allows reuse of an existing non-modal window instead of opening a new modal window
-  if ( !QgsGui::windowManager() || !QgsGui::windowManager()->openStandardDialog( QgsWindowManagerInterface::DialogStyleManager ) )
+  // this allows reuse of an existing non-modal window instead of opening a new modal window.
+  // Note that we only use the non-modal dialog if we're open in the panel -- if we're already
+  // open as part of a modal dialog, then we MUST use another modal dialog or the result will
+  // not be focusable!
+  QgsPanelWidget *panel = QgsPanelWidget::findParentPanel( this );
+  if ( !panel || !panel->dockMode()
+       || !QgsGui::windowManager()
+       || !QgsGui::windowManager()->openStandardDialog( QgsWindowManagerInterface::DialogStyleManager ) )
   {
     // fallback to modal dialog
     QgsStyleManagerDialog dlg( mStyle, this );