fix showEvent calling centerOn

src/chatlog/chatlog.cpp

@@ -728,3 +728,10 @@ void ChatLog::onWorkerTimeout()
         verticalScrollBar()->show();
     }
 }
+
+void ChatLog::showEvent(QShowEvent *)
+{
+    // Empty.
+    // The default implementation calls centerOn - for some reason - causing
+    // the scrollbar to move.
+}

src/chatlog/chatlog.h

@@ -80,6 +80,7 @@ protected:
     virtual void mouseMoveEvent(QMouseEvent* ev);
     virtual void scrollContentsBy(int dx, int dy);
     virtual void resizeEvent(QResizeEvent *ev);
+    virtual void showEvent(QShowEvent *);
 
     void updateMultiSelectionRect();
     void updateTypingNotification();