revert previous fix + code cleaning

src/board/UBBoardController.cpp

@@ -1542,7 +1542,6 @@ void UBBoardController::setActiveDocumentScene(UBDocumentProxy* pDocumentProxy,
         mActiveSceneIndex = index;
         setDocument(pDocumentProxy, forceReload);
 
-        emit initThumbnailsRequired(this);
         updateSystemScaleFactor();
 
         mControlView->setScene(mActiveScene);

src/document/UBDocumentContainer.cpp

@@ -52,6 +52,7 @@ void UBDocumentContainer::setDocument(UBDocumentProxy* document, bool forceReloa
     {
         mCurrentDocument = document;
 
+        emit initThumbnailsRequired(this);
         emit documentSet(mCurrentDocument);
         reloadThumbnails();
     }
@@ -103,8 +104,16 @@ void UBDocumentContainer::addPage(int index)
     emit addThumbnailRequired(this, index);
 }
 
+void UBDocumentContainer::clearThumbPage()
+{
+    qDeleteAll(mDocumentThumbs);
+    mDocumentThumbs.clear();
+}
+
 void UBDocumentContainer::initThumbPage()
 {
+    clearThumbPage();
+
     for (int i=0; i < selectedDocument()->pageCount(); i++)
         insertThumbPage(i);
 }

src/document/UBDocumentContainer.h

@@ -53,6 +53,7 @@ class UBDocumentContainer : public QObject
         void duplicatePages(QList<int>& pageIndexes);
         bool movePageToIndex(int source, int target);
         void deletePages(QList<int>& pageIndexes);
+        void clearThumbPage();
         void initThumbPage();
         void addPage(int index);
         void updatePage(int index);

src/document/UBDocumentController.cpp

@@ -476,7 +476,6 @@ void UBDocumentController::openSelectedItem()
             if (proxy && isOKToOpenDocument(proxy))
             {
                 UBApplication::applicationController->showBoard();
-                UBApplication::applicationController->showBoard();
             }
         }
     }