diff --git a/HISTORY.md b/HISTORY.md
index 20e6cab8..e981dba2 100755
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -66,6 +66,7 @@
 ### 2021-11-23
 * byob: refresh category buttons when hiding / showing blocks
 * gui: refresh category buttons when switching to dev mode and back
+* gui: refresh category buttons when turning built-in extensions on and off
 
 ### 2021-11-19
 * objects, byob, gui: visually indicate empty categories by half-toning their buttons
diff --git a/src/gui.js b/src/gui.js
index 37373150..7ea8f819 100644
--- a/src/gui.js
+++ b/src/gui.js
@@ -3834,6 +3834,7 @@ IDE_Morph.prototype.settingsMenu = function () {
             Process.prototype.enableJS = !Process.prototype.enableJS;
             this.flushBlocksCache('operators');
             this.refreshPalette();
+            this.categories.refreshEmpty();
         },
         Process.prototype.enableJS,
         'uncheck to disable support for\nnative JavaScript functions',
@@ -3849,6 +3850,7 @@ IDE_Morph.prototype.settingsMenu = function () {
                 !SpriteMorph.prototype.showingExtensions;
             this.flushBlocksCache('variables');
             this.refreshPalette();
+            this.categories.refreshEmpty();
         },
         SpriteMorph.prototype.showingExtensions,
         'uncheck to hide extension\nprimitives in the palette',
@@ -4067,6 +4069,7 @@ IDE_Morph.prototype.settingsMenu = function () {
                 !SpriteMorph.prototype.enableFirstClass;
             this.flushBlocksCache('sensing');
             this.refreshPalette();
+            this.categories.refreshEmpty();
         },
         SpriteMorph.prototype.enableFirstClass,
         'uncheck to disable support\nfor first-class sprites',
@@ -4140,6 +4143,7 @@ IDE_Morph.prototype.settingsMenu = function () {
                 !Process.prototype.enableCompiling;
             this.flushBlocksCache('operators');
             this.refreshPalette();
+            this.categories.refreshEmpty();
         },
         Process.prototype.enableCompiling,
         'EXPERIMENTAL! uncheck to disable live\nsupport for compiling',
@@ -4169,6 +4173,7 @@ IDE_Morph.prototype.settingsMenu = function () {
                 !StageMorph.prototype.enableCodeMapping;
             this.flushBlocksCache('variables');
             this.refreshPalette();
+            this.categories.refreshEmpty();
         },
         StageMorph.prototype.enableCodeMapping,
         'uncheck to disable\nblock to text mapping features',
@@ -4182,6 +4187,7 @@ IDE_Morph.prototype.settingsMenu = function () {
                 !StageMorph.prototype.enableInheritance;
             this.flushBlocksCache('variables');
             this.refreshPalette();
+            this.categories.refreshEmpty();
         },
         StageMorph.prototype.enableInheritance,
         'uncheck to disable\nsprite inheritance features',