diff --git a/src/MacVim/MMTextViewHelper.m b/src/MacVim/MMTextViewHelper.m
index 27ec250364..d1a1bbfeaf 100644
--- a/src/MacVim/MMTextViewHelper.m
+++ b/src/MacVim/MMTextViewHelper.m
@@ -747,7 +747,7 @@ static float MMDragAreaSize = 73.0f;
     NSString *chars = [event characters];
     NSString *unmodchars = [event charactersIgnoringModifiers];
     unichar c = [chars characterAtIndex:0];
-    unichar imc = [unmodchars characterAtIndex:0];
+    unichar imc = [unmodchars length] > 0 ? [unmodchars characterAtIndex:0] : 0;
     int len = 0;
     const char *bytes = 0;
     int mods = [event modifierFlags];