src/vs/workbench/browser/parts/views/checkbox.ts/TreeItemCheckbox/registerListener
class TreeItemCheckbox:	private registerListener(node: ITreeItem) {
		if (this.toggle) {
			this._register({ dispose: () => this.removeCheckbox() });
			this._register(this.toggle);
			this._register(this.toggle.onChange(() => {
				this.setCheckbox(node);
			}));
		}
	}