[envvar editor] "edit" does not add new entry if envvar with same prefix exists

see attached screenshot

i have two environment variables set up manually

GST_DEBUG_DUMP_DOT_DIR=/tmp
QT_LOGGING_RULES=qt.multimedia.*=true

my "base" configuration has an envvar GST_DEBUG.

if i select this `GST_DEBUG` entry and press "edit", qtc does not add a new entry to the text field, but selects `_DUMP_DOT_DIR=/tmp`. maybe the "edit" functionality has a heuristics that searches for the `GST_DEBUG` prefix (instead of e.g. `GST_DEBUG=1) and therefore selects the wrong entry in the text field