screen bug: can't su(1) in tcsh

[Lyndon Nerenberg]

While running tcsh inside a "screen(1)" window I find that
running "su bin" does not work whereas "su - bin" does.

The "failure" doesn't generate any error messages - su just
seems to terminate normally (but immediately). The same su
while running csh under screen works fine, as does an su
in tcsh running outside of screen.

Has anyone else run across this and found a fix?

(In case it matters, this is under SunOS 3.4 on a 3/280)

--lyndon  {alberta,ddsw1,utzoo}!ncc!lyndon