User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:62.0) Gecko/20100101 Firefox/62.0 Build ID: 20180609220554 Steps to reproduce: 1- Launch Firefox. 2- Go to https://www.twitch.tv/videos/268868741 3- The problem will appear nearly at (02:53:52). Twitch may delete this video so i uploaded an attachment for the problem. Actual results: Some words of some messages won't show up. Expected results: Be able to see the full text of the messages.

(In reply to rayan from comment #1) > Created attachment 8984730 [details] > twich_chat.gif The video URL of this attachment is (https://www.twitch.tv/videos/263515454) it happens nearly at (02:50:32)

There are some flexboxes in there, fwiw...

Here's a screenshot in Chrome -- as you can see, the one wide message in question is clipped in Chrome (both the little "embedded" piece, as well as the normal chat text above it. The full line of (clipped) text is: "Shoshi19: EXACT split was at 2:21:43.0 - see stream at 02:45:02" So the behavior-difference here is that Firefox is letting this message make the whole chat area wider than its sidebar; whereas in Chrome, just this one message (including its text) is wider.

Edge seems to match Chrome's behavior, too, so this is likely indeed a Firefox bug (unlike kinda-similar bug 1426644).

If I add "min-width: 0" to the div with class="qa-vod-chat", then Firefox changes to match Chrome's rendering. That element has "width: 100%", which is *supposed to* prevent the automatic minimum width from resolving to anything larger than 100% of the container's space. But it does not prevent that in Firefox right now; this is bug 1331692 (which is duped to the more general bug 1136312; I'll mark this as depending on that more general bug. But the description on bug 1331692 is what most directly covers this rendering issue, hence adding that to "see also". I'm keeping this as its own bug since it's worth independently tracking the fact that Twitch is affected by this.)

The twitch video from comment 0 was not working anymore so I had to search for another video with a similar comment where the issue would reproduce. It appears it is related to the fact that those comments that spill out are missing spaces between works. The following STR should be valid: 1. Open browser. 2. Loar the following link: https://www.twitch.tv/videos/347388247 3. Seek to rewind the video to just before time 6:37:50. 4. Let the video run through the time mentioned above. 5. Notice that at 6:37:50, there is a comment from the user "slighltyreckless" saying: "Oooloooolokollkoooooolookolkkokkkoooôoioooo". Actual: Only the first part of the comment is displayed because it spills out due to the lack of spaces in the message. Expected: The browser should display the remaining part of the comment in a new row. I have removed the testcase-wanted tag and added other information after my tests.