diff --git a/AppKit/CPTextView/_CPRTFParser.j b/AppKit/CPTextView/_CPRTFParser.j
index ec76b0a1e..f1f94db99 100644
--- a/AppKit/CPTextView/_CPRTFParser.j
+++ b/AppKit/CPTextView/_CPRTFParser.j
@@ -514,7 +514,7 @@ var kRgsymRtf = {
                 return [self _applyPropChange:sym parameter:param];
 
             case kRTFParserType_char:
-                if((param + '').length)
+                if((param + '') !== 'NaN' && (param + '').length)
                     _currentParseIndex -= (param + '').length;
 
                 return [self _checkChar:sym parameter:param];