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Compilation
===========
Remember all those line format specification variables?
`gnus-summary-line-format', `gnus-group-line-format', and so on. Now,
Gnus will of course heed whatever these variables are, but,
unfortunately, changing them will mean a quite significant slow-down.
(The default values of these variables have byte-compiled functions
associated with them, while the user-generated versions do not, of
course.)
To help with this, you can run `M-x gnus-compile' after you've
fiddled around with the variables and feel that you're (kind of)
satisfied. This will result in the new specs being byte-compiled, and
you'll get top speed again.