"KG" == Kai Großjohann writes:

 KG> Well, inlining a part means that Gnus just inserts the bytes that
 KG> comprise the part into the article buffer.  If you inline a jpeg,
 KG> you get the bytes the jpeg consists of, rather than the actual
 KG> image.

 KG> So I think it is okay that inlining does not obey the charset
 KG> parameter.  And hitting RET on the button works fine (for me).

 KG> What do you think?

That part is text/plain, with a given charset, so it should be inlined
correctly (in particular, preserving charset).

in fact, i see two bugs here:

1) some characters are correctly displayed as cyrillic characters,
   while some others are not.

2) what are those \
\
\
\

which are displayed in the message (see attached snapshot)? Also, try
to move cursor in the contents of the inlined part, -- emacs behaves
rather strangely, --- contents dynamically change, etc...

also, try to select the lines of the inlined part pressing mouse at
the beginning and moving it down...

Best,
v.