diff --git a/indra/newview/lltoast.cpp b/indra/newview/lltoast.cpp
index b9c73076d2ad7a081dae843f1c3b122ad1b8174d..24824a095cb0d25e8f7e9a8dbda6a25d4d9423d8 100644
--- a/indra/newview/lltoast.cpp
+++ b/indra/newview/lltoast.cpp
@@ -208,7 +208,11 @@ void LLToast::setVisible(BOOL show)
 {
 	if(mIsHidden)
 	{
-		// this toast is invisible untill its ScreenChannel will allow it
+		// this toast is invisible after fade until its ScreenChannel will allow it
+		//
+		// (EXT-1849) according to this bug a toast can be resurrected from
+		// invisible state if it faded during a teleportation
+		// then it fades a second time and causes a crash
 		return;
 	}
 
diff --git a/indra/newview/lltoast.h b/indra/newview/lltoast.h
index d4fddc3077dfeecff12f7ddfe8b8edac035e592d..0698c9488022a945b0c93f04181ffa74f8adf7ff 100644
--- a/indra/newview/lltoast.h
+++ b/indra/newview/lltoast.h
@@ -166,7 +166,7 @@ class LLToast : public LLModalDialog
 	bool		mCanBeStored;
 	bool		mHideBtnEnabled;
 	bool		mHideBtnPressed;
-	bool		mIsHidden;  // this flag is TRUE when a toast has faded or was hidden with (x) button
+	bool		mIsHidden;  // this flag is TRUE when a toast has faded or was hidden with (x) button (EXT-1849)
 };
 
 }