The selection is wrongly saved if you choose the "Copy" option using keyboard navigation

[Softvision-CristinaBadescu]

[Notes]:

• This issue is not reproducible for selections smaller than 400px width.
• Also, you'll encounter the "catcher is not defined" error notification from Investigate "catcher is not defined" #2996 issue.
• This issue is also reproducible for manual selections.

[Affected versions]:

• Nightly 59.0a1
• Screenshots 28.0.0 dev version

[Affected Platforms]:

• All Windows
• All Mac OS
• All Linux

[Prerequisites]:

• Have the "xpinstall.signatures.required" pref set to "false" and "extensions.legacy.enabled" pref set to "true".
• Have the latest Firefox Screenshots v28.0.0 installed from here on a new clean profile.

[Steps to reproduce]:

1. Open Firefox browser with the profile from prerequisites and navigate to a website, eg. http://money.cnn.com/technology/.
2. Click "Page actions" button and select "Take a Screenshot".
3. Perform an automatically large selection (at least 400px).
4. Rapidly press "Tab" key twice to focus "Copy" button.
5. Press "Enter" key and observe the behavior.

[Expected result]:

• The selection is copied to clipboard and a "Shot Copied" notification appears.

[Actual result]:

• The selection is copied to clipboard but it's also saved and opened in a new tab.

[Additional notes]:

• This issue is not reproducible if you click the "Copy" button.

• This issue is not reproducible with Firefox Screenshots 25.0.0.

• Here is a screenshot with the browser console error:
  

• Here is a screen recording of this issue:
  

[chenba]

I cannot reproduce this with latest Screenshots.

[chenba]

Sorry, I misunderstood the STR. I can reproduce it.

[chenba]

This bug also highlights an inconsistency. With full-page and visible shots, the enter key does not have a default action, whereas the enter key would trigger the primary button's action (Save or Download) for selection shots.

[Softvision-CristinaBadescu]

This issue is no longer reproducible using Firefox Screenshots v28.0.0dev installed from here, on latest Nightly build 60.0a1 (2018-01-28), on Windows 10 x64, Mac 10.12.6 and Arch Linux 4.12.