diff --git a/src/apps/webpositive/BrowserApp.cpp b/src/apps/webpositive/BrowserApp.cpp
index e4a0627776..fe99ec9e5f 100644
--- a/src/apps/webpositive/BrowserApp.cpp
+++ b/src/apps/webpositive/BrowserApp.cpp
@@ -89,7 +89,7 @@ BrowserApp::~BrowserApp()
 	delete fCookies;
 	delete fCookieJar;
 
-	if (fAboutWindow != NULL)
+	if (fAboutWindow != NULL && fAboutWindow->Lock())
 		fAboutWindow->Quit();
 }