In bug 53617, comment 53 Rod lists the "current Linux code" and "current Mac code" that maps the field, button, and list system fonts in nsRuleNode.cpp. None of this code is ever executed. All the code is conditioned on "if (eCompatibility_NavQuirks == mode)" and earlier in the file we have: 1828 nsCompatibility mode = eCompatibility_Standard; 1829 1830 if (sysID == eSystemFont_Field || 1831 sysID == eSystemFont_List || 1832 sysID == eSystemFont_Button) { 1833 nsCOMPtr<nsIPref> prefService(do_GetService(NS_PREF_CONTRACTID)); 1834 if (prefService) { 1835 PRBool useEitherMode; 1836 if (NS_SUCCEEDED(prefService->GetBoolPref("layout.forms.use_standard_or_quirks", &useEitherMode))) { 1837 if (useEitherMode) { 1838 aPresContext->GetCompatibilityMode(&mode); 1839 } 1840 } 1841 } 1842 } Now the pref layout.forms.use_standard_or_quirks is not defined anywhere in a default profile. So get GetBoolPref fails and |mode| stays standards mode. As a result, we always use whatever GetSystemFont returned, which is utterly bogus in many cases (see bug 130632 and bug 130635).

See Comment 58 on bug 53617; directly relevant: http://bugzilla.mozilla.org/show_bug.cgi?id=53617#c58

See also bug 53524 and bug 131452 (and bug 91602).

See also #53360

Duplicate of bug 131452? Or do you think we should have used some of that code?

No, it's better to just fix any issues we have at the system font code level so everything using the system fonts gets the fixes. So removing this code was the right thing to do. *** This bug has been marked as a duplicate of 131452 ***