diff --git a/biscuit/core/components/editors/texteditor/__init__.py b/biscuit/core/components/editors/texteditor/__init__.py
index b3735e7a..5a4bd4a9 100644
--- a/biscuit/core/components/editors/texteditor/__init__.py
+++ b/biscuit/core/components/editors/texteditor/__init__.py
@@ -39,6 +39,7 @@ def __init__(self, master, path=None, exists=True, minimalist=False, *args, **kw
         self.text.bind("<Configure>", self.on_change)
 
     def unsupported_file(self):
+        self.text.highlighter.lexer = None
         self.text.show_unsupported_dialog()
         self.linenumbers.grid_remove()
         self.scrollbar.grid_remove()