Everytime I try to use “Show Fonts…” (command-T) Mathematica pops up a window that says “Internal Error” (with the option of continuing or crashing). The dialog box gives the option of selecting “Crash” to send a report, but it seems Mathematica just crashes and then causes the Apple crash report dialog to appear (yes, I sent the report to Apple).
I haven’t seen any other posts about this since the release of Sierra.
Me too, very annoying. Of course, if you are changing the fonts of, say, a single text cell, then
this can be circumvented by opening the option inspector and setting fonts in the format section.
Clearly, this will be fixed hopefully soon.
I just installed version 11.0.1 and the problem is not solved. Instead, the show fonts line in the Format Menu
disappeared. It is still there but inactive (shaded)… Too bad