--- a/eric6/QScintilla/Lexers/SubstyledLexer.py	Wed Jun 26 19:41:11 2019 +0200
+++ b/eric6/QScintilla/Lexers/SubstyledLexer.py	Thu Jun 27 19:05:28 2019 +0200
@@ -183,7 +183,8 @@
                 subStyleStart = editor.SendScintilla(
                     editor.SCI_ALLOCATESUBSTYLES, baseStyleNo, subStyleLength)
                 if subStyleStart < 0:
-                    subStyleLength = 0
+                    continue
+                
                 subStyleIndex = -1
                 for subStyleKey in sorted(subStylesData.keys()):
                     subStyleIndex += 1