Preset buttons not working in editor

[Xento]

I can't add preset buttons via the editor: Uncaught TypeError: Cannot add property preset_buttons, object is not extensible at ShutterRowEditor._addPresetItem (shutter-row.js:495:41) at H.handleEvent (shutter-row.js:19:7199)

When I define them in code it shows up the editor isn't working: shutter-row.js:664 Uncaught TypeError: Cannot add property undefined, object is not extensible at ShutterRowEditor.presetChanged (shutter-row.js:664:67) at H.handleEvent (shutter-row.js:19:7199) at o (fire_event.ts:76:8) at ShadowRoot. (ha-form.ts:180:7) at o (fire_event.ts:76:8) at F.value (hui-action-editor.ts:190:7) at D.handleEvent (lit-html.ts:2010:29) at Object.notifySelected (mwc-list-base.ts:409:14) at f.setSingleSelectionAtIndex (mwc-list-foundation.ts:410:18) at f.setSelectedIndex (mwc-list-foundation.ts:194:12)