Merge pull request #2691 from zerline/focus-fix2

Focus/blur on a RadioButtons widget.

Author: vidartf

packages/controls/src/widget_selection.ts

@@ -403,6 +403,21 @@ class RadioButtonsView extends DescriptionView {
         this.touch();
     }
 
+    /**
+     * Handle message sent to the front end.
+     */
+    handle_message(content: any) {
+        if (content.do == 'focus') {
+            const firstItem = this.container.firstElementChild as HTMLElement;
+            firstItem.focus();
+        } else if (content.do == 'blur') {
+            for (let i = 0; i < this.container.children.length; i++) {
+                const item = this.container.children[i] as HTMLElement;
+                item.blur();
+            }
+        }
+    }
+
     container: HTMLDivElement;
 }