Comment 25 for bug 1425387

OTOH I am fully aware of the pango-glyph-string-x-to-index one. But in the usage sense we don't really need that since we don't really want to use any positioning within the cluster as far as i am concerned. But relocation of the glyph in this issue isn't acceptable. I am also working on a patch that will use special cursor to progress through the ligature by percentage rendering so cursor don't get lock at the first ligature until you get the actual position pass it. It works as good as it get so far. I don't think that really matter the Thai usage. Retype the whole cluster is acceptable, rendering it that way isn't.