At work some years (I had typed 'tears'!!!) ago, we were using an expensive XTerm Windows Program on either 3.1 or 95 - a net sniffer revealed that when the window was covered by another - it would barrage the server with requests - bogging down the LAN. Also, each time an XTerm window was opened and closed it chewed RAM and the only way to recover it was to reboot - shutting the app did not recover it.... a phone call produced an 'upgrade' which was more useful...