Changed with changeset 849d7434c2e1. Will be part of release 21.5.
Btw, the "What's this?" help text already explained that and contains even more
information.
It seems that now environment variables should be separated by space. Previously I've used semicolons. It would be useful to mention what separator to use in the entry field tooltip.
In Eric 21.2 setting environment variables in run/debug dialogs is broken.
In 21.1 running attached script shows PYTHONPATH and BLAH environment variables if they were set in the run/debug dialog, but in 21.2 it does not.