don't use DesignMetrics

src/chatlog/content/text.cpp

@@ -202,8 +202,6 @@ void Text::ensureIntegrity()
     if(!doc)
     {
         doc = new CustomTextDocument();
-        doc->setUndoRedoEnabled(false);
-        doc->setUseDesignMetrics(true);
         doc->setDefaultFont(defFont);
 
         if(!elide)

src/chatlog/customtextdocument.cpp

@@ -25,6 +25,8 @@ CustomTextDocument::CustomTextDocument(QObject *parent)
     : QTextDocument(parent)
 {
     setDefaultStyleSheet(Style::getStylesheet(":ui/chatArea/innerStyle.css"));
+    setUndoRedoEnabled(false);
+    setUseDesignMetrics(false);
 }
 
 QVariant CustomTextDocument::loadResource(int type, const QUrl &name)