Shortcut to page on another website causes missing OPE/APE buttons

Description

Steps to reproduce:

1. Edit Page1 in APE mode.
2. Change the Shortcut settings to "Shortcut to page on another website".
3. Set the External Link to e.g. "https://www.google.com".
4. Click the On-Page Editing (OPE) button.

Expected:
Switches to OPE mode and shows "www.google.com refused to connect" in main pane.

Actual:

• You are not in view OPE mode but see an in-progress icon on the OPE button.
• The OPE/APE button is hidden, and the main pane is blank after the page reloads.

Observed: Script error: Refused to display 'https://www.google.com/' in a frame because it set 'X-Frame-Options' to 'sameorigin'.