diff --git a/uppsrc/CtrlCore/CtrlCore.h b/uppsrc/CtrlCore/CtrlCore.h
index f3467c1dd..050eec490 100644
--- a/uppsrc/CtrlCore/CtrlCore.h
+++ b/uppsrc/CtrlCore/CtrlCore.h
@@ -42,6 +42,7 @@ INITIALIZE(CtrlCore)
 
 #ifdef _MULTITHREADED
 void EnterGuiMutex();
+bool TryEnterGuiMutex();
 void LeaveGuiMutex();
 
 int  LeaveGuiMutexAll();
@@ -51,6 +52,7 @@ bool ThreadHasGuiLock();
 #else
 inline void EnterGuiMutex() {}
 inline void LeaveGuiMutex() {}
+inline bool TryEnterGuiMutex() { return true; }
 
 inline int  LeaveGuiMutexAll() { return 0; }
 inline void EnterGuiMutex(int) {}
diff --git a/uppsrc/CtrlCore/CtrlMt.cpp b/uppsrc/CtrlCore/CtrlMt.cpp
index ae18975fa..fcd18675e 100644
--- a/uppsrc/CtrlCore/CtrlMt.cpp
+++ b/uppsrc/CtrlCore/CtrlMt.cpp
@@ -29,6 +29,15 @@ void EnterGuiMutex(int n)
 	LLOG("EnterGuiMutex " << sGLockLevel << ' ' << IsMainThread());
 }
 
+bool TryEnterGuiMutex()
+{
+	if(sGLockLevel == 0 && sGLock.TryEnter()) {
+		sGLockLevel++;
+		return true;
+	}
+	return false;
+}
+
 void LeaveGuiMutex()
 {
 	LLOG(">LeaveGuiMutex " << sGLockLevel << ' ' << IsMainThread());