scroll selected custom category button into view

HISTORY.md

@@ -42,6 +42,7 @@
 
 ### 2021-10-14
 * gui, byob, objects: scroll custom category buttons if there are more than 6
+* gui, byob: scroll selected custom category button into view
 
 ### 2021-10-12
 * scenes, store: store single palette setting per project (for making extensions)

src/byob.js

@@ -1756,7 +1756,12 @@ BlockDialogMorph.prototype.init = function (target, action, environment) {
     this.categories.buttons = [];
 
     this.categories.refresh = function () {
-        this.buttons.forEach(cat => cat.refresh());
+        this.buttons.forEach(cat => {
+            cat.refresh();
+            if (cat.state) {
+                cat.scrollIntoView();
+            }
+        });
     };
 
     this.createCategoryButtons();

src/gui.js

@@ -1267,7 +1267,12 @@ IDE_Morph.prototype.createCategories = function () {
     this.categories.buttons = [];
 
     this.categories.refresh = function () {
-        this.buttons.forEach(cat => cat.refresh());
+        this.buttons.forEach(cat => {
+            cat.refresh();
+            if (cat.state) {
+                cat.scrollIntoView();
+            }
+        });
     };
 
     function changePalette(category) {