UMSG does not seem to be working correctly
i.e the message continues to be displayed and not cleared

In a screen function.
I have a UMSG in a called LS
which displays the message in default logic
'Retrieving records, please wait...'

However , once control is passed back to the main screen,
the message remains.

this did not happen in V4.0

We're running VMS v5.5 r334 green screen on our development box and I have not noticed a problem with the UMSG's. Then again, we've got help messages on virtually every input field so a problem such as you described might not be immediately apparent to us.

Are you running VMS v5.5 r334 in green screen or are you using the GUI client?