tramp with shell mode and absolute paths

[Matthew Curry]

Hi all:

I've recently noticed the wonders of tramp and running shells on
remote machines in emacs, great time-saver, thanks all!

Sorry if this as been mentioned before, but searches came up empty.
I notice on my emacs (fedora 11's, i.e. 23.1.1) in shell-mode (M-x
shell), whenever I do a cd with an absolute path (or a cd with no
argument or tildes), it messes up the current directory shell-mode
thinks it's in and gets rid of the "tramp-ness", so to speak, and
tab-autocomplete will now think any further paths are on the local
machine.

For instance, *Buffer List* shows this on spawning a remote shell with
M-x shell:
  * *shell*                 81  Shell:run         /scp:soma:/home/e3/

I do a "cd /" (or just "cd", or "cd ~") and now *Buffer List* shows this:
  * *shell*                114  Shell:run         /

And from then on, tab autocomplete will look at the local machine's
filesystem instead of the remote one.

So my question is a) is this a known problem and b) is there a way to
make shell-mode respond to absolute paths more correctly?

I'm not even sure if the problem is in tramp or in shell-mode to be honest.

Thanks,

-Matt