Created attachment 8846411 [details] mathml.jpg User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20170127092049 Steps to reproduce: I just went to the torture text: https://developer.mozilla.org/en-US/docs/Mozilla/MathML_Project/MathML_Torture_Test Actual results: And I saw that tests 18 and 23 (at least) have an issue: lines are huge! Expected results: I was expecting to get in the right column what we can see in the left one.
WFM in Fx51.0 & Fx53.0b1 on Win10. Did you test with a fresh profile? https://support.mozilla.org/t5/Install-and-Update/Use-the-Profile-Manager-to-create-and-remove-Firefox-profiles/ta-p/2914
I also tested with 54.0a2 (2017-03-12) (64 bits) on Linux. Both in normal launch and with add-ons disabled. Same problem. By the way, what does "WFM" means?
(In reply to contact from comment #2) > By the way, what does "WFM" means? https://developer.mozilla.org/en-US/docs/Mozilla/Bugzilla/What_to_do_and_what_not_to_do_in_Bugzilla#Resolving_bugs_as_WORKSFORME
WFM with FF52 on Win 7.