Every now and then I somehow manage to enter Ctrl-S into urxvt and freeze it, still don't know how I do that. Anyway, each time I have to Google "urxvt frozen"

Every now and then I somehow manage to enter Ctrl-S into urxvt and freeze it, still don't know how I do that. Anyway, each time I have to Google "urxvt frozen" to find what to do.