Run away 4GL's

Informix 5.10 SE 4GL 4.20 Sun E10000 Solaris 2.5.1 (Don't ask) 450 ish concurrent users connecting using telnet from win3.11/NT Workstation clients Occasionally I'm getting (a couple a day) 4gl clocking excessive CPU, note the 4ge not the sqlexec. The PID tree from the program is fine and everything traces back correctly to the login shell. The sqlexec is 'sleeping' and the stack trace on the 4ge indicates the user is sat in a screen menu. The 4ge however is clocking CPU in real time, ie for every real second the process clocks 1 second of CPU - the joys of an E10000 I suppose ;-) Trussing the 4ge show that the process in continuously polling stdin, a single byte read as if it's waiting for a keystoke which tallies back to where they are in the code. I can not reproduce the problem via CNTL-S/Q combinations, unplugging the PCs from the network, holding down a key continuously. It happens to a number of different 4ges, for users on different subnets. Oddly sending any message to the runaway screen clears the problem. It also never happened on the old E2000 Solaris 2.4 and Informix 4gl 4.14 SE 5.06. The termcaps on both machines are the same. Anybody got any other ideas Paul Watson