After performing a shot and clicking the "Back" button, you are redirected to the "Saving your shot..." page and the "Forward" one is not actionable

[Softvision-CristinaBadescu]

[Notes]:

• If you click again the "Back" button, you are redirected to the "/creating" page and the "Forward" one is actionable, but still redirects you on the "Saving your shot..." page.Only if you click the "Forward" button and afterwards the "Refresh" button, the page shot is displayed.
• Also, if you refresh the page while the "/creating" url is displayed, you are stuck on the "Saving your shot..." page, even if the saved shot url is correctly displayed in the address bar.

[Affected versions]:

• Firefox 60.0 and up

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Steps to reproduce]:

1. Open Firefox browser with the profile from prerequisites and navigate to a website.
2. Click the "Page actions" button and select "Take a Screenshot".
3. Perform a selection and click the "Save" button.
4. Click the "Back" button and observe the "Forward" button.

[Expected result]:

• The "Forward" button is actionable.

[Actual result]:

• The "Forward" button is unactionable.

[Additional notes]:

• Here is a screen recording of this issue:
  

[chenba]

@Softvision-CristinaBadescu I just tried addon versions 28.1.0 and 25.0.0 against a server with #4011 applied, and I was not stuck on the "Saving your shot..." screen as you reported in #3995 (comment) Or did you mean you still see the loader but not stuck there?

I will reapply #4011.

[chenba]

@Softvision-CristinaBadescu Could you re-verify with an older version of the addon (pre-60) with https://screenshots.dev.mozaws.net as the server? You should be taken to the shot, but the back button will probably be clickable. If you click back to the loader, clicking forward should take you to the shot.

[Softvision-CristinaBadescu]

Thanks @chenba :) ! This issue is not reproducible on older Firefox Screenshots versions, such as 19.2.0, 23.0.0, 25.0.0 and 28.0.0. When I click the "Back" button, the "Forward" one is actionable and after I click it, I am redirected to the shot page. Tested on latest Nightly build 62.0a1 (2018-05-15), on Windows 10 x64, Mac 10.12.6 and Arch Linux 4.12.

This issue does not apply to the Firefox Screenshots versions above 30.1.0, because the "Back" button is unactionable.