object key deletion fix

Author: b3m2a1

package.json

@@ -59,7 +59,7 @@
   "devDependencies": {
     "@babel/core": "^7.5.0",
     "@babel/preset-env": "^7.5.0",
-    "@jupyterlab/builder": "^3.0.0",
+    "@jupyterlab/builder": "^4.0.4",
     "@phosphor/application": "^1.6.0",
     "@phosphor/widgets": "^1.6.0",
     "@types/bootstrap": "^5.1.11",

src/widget.ts

@@ -759,8 +759,8 @@ export class ActiveHTMLView extends DOMWidgetView {
                         if (debug) {
                             console.log(this.el, "Removing Event:", prop);
                         }
-                        this.el.removeEventListener(prop, this._currentEvents[prop][1]);
-                        this._currentEvents.delete(prop);
+                        this.el.removeEventListener(prop, current[prop][1]);
+                        delete current[prop];
                     }
                 }
             }
@@ -815,7 +815,7 @@ export class ActiveHTMLView extends DOMWidgetView {
                             console.log(this.el, "Removing On Handler:", prop);
                         }
                         this.model.off(prop, current[prop][1], this);
-                        current.delete(prop);
+                        delete current[prop];
                     }
                 }
             }