The "Save" and "Cancel" buttons from the expiration date cannot be focused using the keyboard

[Softvision-CristinaBadescu]

[Affected versions]:

• Firefox 60.0 and up

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• Have a saved shot link.

[Steps to reproduce]:

1. Open the Firefox browser with the profile from prerequisites and navigate to the saved shot link.
2. Click the "expires in ..." button and select a period.
3. Press the "Tab" key once and observe the behavior.

[Expected result]:

• The "Save" button is focused.

[Actual results]:

• The "Delete" button is focused.

[Notes]:

• Here is a screen recording with the issue:
  

[Softvision-CristinaBadescu]

This issue is no longer reproducible using the latest Firefox Screenshots dev version installed from here, on latest Nightly build 62.0a1 (2018-06-18), on Windows 10 x64, Mac 10.13.5 and Arch Linux 4.12.

However, it seems that the "Enter" key does not access these buttons. I've filed the issue here: #4561 .