When and how is the “First Line Match” setting of language grammars considered?
In my experiments it doesn't seem to have any effect at all: For example, I'd like TextMate to use the RSpec grammar for all *.rb having a first line matching '.*spec_helper.*', but it seems to always use the Rails grammar instead (even for newly created files). I suspect TextMate remembers some kind of manual override – if so, how can I reset this override? Is there any way to see (debug) how TextMate choses the grammar?