Inconsistent matching with Ligatures

[rschmukler]

I'm currently experimenting with using ligatures and seeing some interesting behavior. I realize that ligatures are a bit of a fringe feature so please excuse the rarity of this bug.

Basically, by default, only the closing delimiter receives color. However, if I move the cursor over the opening ligature (ie. either character) or the closing delimiter the entire ligature gets highlighted correctly.

Eg:

#(foo) will, at first, only have ) highlighted, but once I move the cursor over either ) or # or ( then #( will be correctly colored.

This also might be an issue with how font-locking is applied to composition ligatures, in which case, I'm not sure there's anything to be done...

[Fanael]

That honestly sounds like a problem with Emacs display engine more than anything, mind asking upstream?