diff --git a/Telegram/SourceFiles/core/sandbox.h b/Telegram/SourceFiles/core/sandbox.h
index f2b591706..01ef9c5c8 100644
--- a/Telegram/SourceFiles/core/sandbox.h
+++ b/Telegram/SourceFiles/core/sandbox.h
@@ -78,6 +78,7 @@ private:
 
 	void closeApplication(); // will be done in aboutToQuit()
 	void checkForQuit(); // will be done in exec()
+	void checkForEmptyLoopNestingLevel();
 	void registerEnterFromEventLoop();
 	void incrementEventNestingLevel();
 	void decrementEventNestingLevel();