Changing the identifiers defined by a @font-feature-values section using the style editor has no effect. Neither does adding or removing identifiers or entire @font-feature-values sections. To reproduce: - Open https://jsfiddle.net/t128qyq4/ . - Open Firefox' style editor. - Select the fiddle's 5-rule stylesheet. - Change both the identifier definition and its use from variant-g to variant-x. Expected results: - The third paragraph retains its variant style, looking like the second paragraph. Actual results: - The third paragraph loses its variant style, looking like the first paragraph.

Can't reproduce with your jsfiddle, the three paragraphs look the same when I open it, like if Open Sans does not have OpenType features. Could you upload a simpler STR please ?

I've updated the fiddle to pull a font I know is good. https://jsfiddle.net/t128qyq4/1/

Thanks, I reproduced (it changes the look of the lowercase 'g' )

Seems to be fixed in the current Nightly.

Yes, this was fixed by bug 1355721. But we should add a test if there isn't one already. Would any of you be interested in submitting one?