"This isn’t a standard Web page, so you can’t take a screenshot of it." notification is displayed on certain pages when the "Take a Screenshot" context menu option is used

[Softvision-CristinaBadescu]

[Affected versions]:

• Firefox 61.0.1 and up

[Affected Platforms]:

• All Windows
• All Mac
• All Linux

[Prerequisites]:

• Firefox Screenshots was used before.
• The onboarding tour was already visited.

[Steps to reproduce]:

1. Open the Firefox browser and navigate to the "https://testpilot.firefox.com/" page.
2. Right click and select the "Take a Screenshot" context menu option.
3. Observe the behavior.

[Expected result]:

• The Screenshots overlay is displayed.

[Actual result]:

• The "This isn’t a standard Web page, so you can’t take a screenshot of it." notification is displayed.

[Notes]:

• This issue is also reproducible on "https://addons.mozilla.org/en-US/firefox/" page.
• This issue is also reproducible using the latest Firefox Screenshots dev or stage version.
• This issue is not reproducible using the "Take a Screenshot" option from the "Page Actions" button because the mozillaAddons permission partially fixed the ability to take a screenshot on these two websites.
• Here is a screen recording with this issue:

[chenba]

Duplicate of https://github.com/mozilla-services/screenshots/issues/3778

[9037568]

Where is the definition of a "standard Web page" so that users may know which web pages they should expect Firefox to fail miserably at capturing?

[comeonmozilla]

9037568 is right, or provide steps to ["magic mozillaAddons permission"] (wish we had that term in intel bug report meetings back in the stone age, can mozilla devs share the process/steps to enable "magic permission" so users can screenshot webpages) As far as this issue, 4526 , and 3778 can a dev point out the "USER" fix that caused the issue to be "closed". Or clarify that it is still being worked on, or that it is impossible to fix.

seems the issue is how mozilla firefox handles webpage frames when taking screenshots

pdf may work for some users (print option - print selected frame) - ensure page setup size appropriate to capture entire page .

[Gartral]

i'm on 68.0.1 and I can't screenshot my router pages at 192.168.1.1 and 192.168.100.1 locally... firefox renders them fine so why can't I take a screenshot?

[bsehri]

I'm trying to take full page screenshots in about:performance and about:config in firefox 74, but getting the same message. is there solution for this?

[wallrj]

There's a partial explanation here: https://support.mozilla.org/en-US/kb/firefox-screenshots#w_why-doesnt-firefox-screenshots-work-on-certain-pages

Screenshots should work on almost all web pages. Certain pages that contain the HTML

are not fully supported and may not be shootable.

Additionally, some pages with special permissions to modify Firefox, like Test Pilot and addons.mozilla.org, are unsupported due to strict security rules designed to prevent page manipulation.

Lastly, certain browser pages like the Firefox home and Preferences pages are not supported. These pages are built using a different language than the rest of the Web.

It'd be nice if the popup error message linked to or included that information.