I have several ISPF screens on z/OS, and I found it confusing knowing which one I was on. I solved it by making the screen with the all powerful userid displayed in red, and the “normal” screen in multi colours, and the screen with no authority in green.
With x3270 you can use Options -> Colour Scheme -> Default 3279 |Green, to use a predefined colour scheme.
I created my own colour scheme by editing ~./x3270pro and adding
! define the list of colour schemes x3270.schemeList: Default 3279: default\n\ Bright: bright\n\ Reverse: reverse\n\ Green Screen: greenScreen\n\ Colin: colin ! now define my list x3270.colorScheme.colin: \ black deepSkyBlue pink red \ green turquoise yellow white \ black blue3 orange purple \ paleGreen paleTurquoise2 grey white \ white black dimGray \ 4 2 1 15
You can now use the command to start a session with this scheme.
x3270 -model 5 -scheme colin tso@localhost:3270