Inconsistent block comment coloring

[Yaroslav Bulatov]

I experience some inconsistency when I enclose a big block in comments --
the lines in the middle don't change their color. Refreshing the screen --
CTRL-L doesn't do anything. The only way to get them to assume comment
color is to edit those lines. But then again, when I remove comment tags,
color of some lines isn't restored. What could be the cause of this?

Yaroslav