diff -up texstudio2.11.2/.qtsingleapplication texstudio2.11.2/
diff -up texstudio2.11.2/texstudio.pro.qtsingleapplication texstudio2.11.2/texstudio.pro
--- texstudio2.11.2/texstudio.pro.qtsingleapplication	2016-10-11 15:02:44.000000000 -0500
+++ texstudio2.11.2/texstudio.pro	2016-12-08 10:17:52.533768367 -0600
@@ -35,7 +35,13 @@ QT += \
     DEFINES += PHONON
 }
 contains($$list($$[QT_VERSION]), 4.3.*):message("qt 4.3.x")
-else:include(qtsingleapplication/qtsingleapplication.pri)
+else: {
+isEmpty(USE_SYSTEM_QTSINGLEAPPLICATION){
+include(qtsingleapplication/qtsingleapplication.pri)
+} else {
+CONFIG += qtsingleapplication
+}
+}
 
 # ##############################
 # precompile_header: PRECOMPILED_HEADER = mostQtHeaders.h