User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040614 Firefox/0.8 Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040614 Firefox/0.8 With the TeX and Mathematica 4.1 fonts installed, Mozilla displays most MathML correctly, but fails to locate glyphs for U+2061 and U+2062. Checking out http://www.unicode.org/charts/PDF/U2000.pdf I found that these characters are 'invisible function mapping' and 'invisible multiplication' characters. It is therefore entirely appropriate that Mozilla should insert these. However, the key word here is "invisible"... it appears as though these should not be displayed. I have ghostscript's Standard Symbols L installed; this is not the same font as Adobe's Type1 which is apparently the one required (I don't want to install Acroread on my system). I followed Jungshik Shin's recommendation as outlined in http://bugzilla.mozilla.org/show_bug.cgi?id=128153#c90 to allow fontconfig to locate the Symbol font; obviating this rather cumbersome procedure is what bug #236880 was filed for. My hunch is that I'm missing a font of some sort. What confuses me though is that it appears that, for example, U+2062 is not included into all statements sporting implicit multiplication. For example, in the referenced URL, the integral of f(x) dx displayed under 'You can also make displayed equations, such as the following ones:' seems to have a fair amount of implicit multiplication but does not display the '2062' glyph-not-found box anywhere. Directly above, in the sentence 'write vector equations Y = aX + b', it does appear between the a and X. And it appears all over the place in the polynomial expansions at the bottom of the page. I couldn't find any reference to this anywhere. I am using Debian GNU/Linux testing/unstable (mostly testing with a few unstable packages). Let me know if there's anything I can do to make the problem clearer. Reproducible: Always Steps to Reproduce: 1. Open the page in question. Happens every time. Actual Results: Glyphs were displayed incorrectly. Expected Results: Presumably invisible glyphs should not be displayed.

This is a screen shot of http://www.mozilla.org/projects/mathml/demo/basics.xhtml taken around the polynomial expansion section of the page, in which many U+2062 glyphs are rendered, somewhat ruining the experience ;)

This looks fine for me with a gtk2/xft 1.7 branch build as well as a plain trunk pull and even a 1.6 build. I don't have special fonts installed, however...

This problem will just go away if bug 205387 was fixed on Linux (Xft or core fonts). We don't have such issues on Windows anymore because invisible characters are treated as ignorable characters during rendering, per the patch that was checked in from that bug.

This works for me. I suggest closing this bug if everybody agree.