Shortcut links don't clear target setting when changing back to "no shortcut"

Description

If you set up a shortcut link on a page and choose an "Open in" option, it doesn't clear that setting when you change it back to "No shortcut."

Steps to reproduce:

1. Navigate to any page type currently in the navigation (or in a listing somewhere) in the back-end.
2. Click the Settings tab.
3. Click Manage next to Shortcut.
4. Choose either the "Shortcut to another content item" or "Shortcut to a page on another website" option.
5. Choose either "Open the link in a new window" or "Open the link in the whole window" as the Open in option.
6. Enter an external URL or choose a page.
7. Click Save.
8. Publish the page.
9. Click Manage again to reopen the shortcut settings.
10. Change the shortcut type to No shortcut and click Save.
11. Publish the page.
12. On the front-end of the site, click the page in the navigation (or in the listing).

Expected
You can change the "Open in" option if the shortcut type is "No shortcut".

Actual
The page opens in a new window because the "Open in" drop down is still populated with the previous selection, even though the shortcut was turned off.