User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0 Build ID: 20171103003834 Steps to reproduce: Press ctrl + shift + m on windows or linux and click on firefox screenshots icon in the taskbar. Actual results: nothing Expected results: It should be possible to take a screenshot.

Thanks for filing! When you the "taskbar", do you mean the toolbar at the top of Responsive Design Mode (with DPR, throtting, screenshot), or do you mean in the DevTools toolbox (you can enable the screenshot button from toolbox options)? When I try the screenshot button in the RDM toolbar, the viewport does a camera flash, and the screenshot is added to the Downloads list. Can you check the Browser Console[1] to see if any errors are shown while doing this? [1]: https://developer.mozilla.org/en-US/docs/Tools/Browser_Console

Im sorry for the unclear explanation, i didnt have much time as i did this at work. I started an empty profile from about:profiles In there i opened any website and opened RDM, then i used the "..." in the URL Bar and clicked "Take a screenshot" (the scissors icon). When im not in RDM i can select a part of the page and much more (upload image to cloud etc.). But that does not happen in RDM, i instead get no response whatsoever. The screenshot icon at the top RDM works as expected though. :) The console is empty.

Ah of course, I totally forgot about that type of screenshot, sorry! :) I believe this may have been recently fixed in Nightly by bug 1394841. Could you try downloading the latest Nightly to see if it is fixed there?

Yes, its seems fixed :) Maybe the Buttons in the upper right should be more responsive though, but thats a different ticket that one should make. Thanks! And sorry for not testing in nightly first.

Great, thanks for testing! :)