diff --git a/Lib/idlelib/ColorDelegator.py b/Lib/idlelib/ColorDelegator.py
index 0610c4b..c74865d 100644
--- a/Lib/idlelib/ColorDelegator.py
+++ b/Lib/idlelib/ColorDelegator.py
@@ -50,6 +50,10 @@
             self.config_colors()
             self.bind("<<toggle-auto-coloring>>", self.toggle_colorize_event)
             self.notify_range("1.0", "end")
+        else:
+            # No delegate - stop any colorizing
+            self.stop_colorizing = True
+            self.allow_colorizing = False
 
     def config_colors(self):
         for tag, cnf in self.tagdefs.items():
diff --git a/Misc/NEWS b/Misc/NEWS
index abb5068..e2ed81c 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -23,6 +23,8 @@
 IDLE
 ----
 
+- Issue #17613: Prevent traceback when removing syntax colorizer in IDLE.
+
 - Issue #1207589: Backwards-compatibility patch for right-click menu in IDLE.
 
 - Issue #16887: IDLE now accepts Cancel in tabify/untabify dialog box.