disable system title bar by default

Author: tanlerr

src/core/sessionconfig.cpp

@@ -127,7 +127,7 @@ void SessionConfig::loadCore(const QJsonObject &p_session) {
   if (!isUndefinedKey(coreObj, QStringLiteral("systemTitleBar"))) {
     m_systemTitleBarEnabled = readBool(coreObj, QStringLiteral("systemTitleBar"));
   } else {
-    m_systemTitleBarEnabled = true;
+    m_systemTitleBarEnabled = false;
   }
 
   if (!isUndefinedKey(coreObj, QStringLiteral("minimizeToSystemTray"))) {

src/core/sessionconfig.h

@@ -198,7 +198,7 @@ class SessionConfig : public IConfig {
   OpenGL m_openGL = OpenGL::None;
 
   // Whether use system's title bar or not.
-  bool m_systemTitleBarEnabled = true;
+  bool m_systemTitleBarEnabled = false;
 
   // Whether to minimize to tray.
   // -1 for prompting for user;