[9fans] troff ignoring .eo/.ec after first time

[Pietro Gagliardi]

Hello. Try this:

        tbl /n/sources/contrib/pietro/plan9prog.ms | troff -ms | page
On about the third page, some code begins, but at the print()  
statement at the end there is some strangeness. If you look inside  
the .ms file, there are some .eo and .ec requests. .eo turns off \x  
and .ec turns it back on. But why is it ignored after that first  
page, which works correctly?