diff -r 874fdd14d3a2 -r 43248bafe9b2 eric6/DebugClients/Python/DebugClientBase.py --- a/eric6/DebugClients/Python/DebugClientBase.py Mon Feb 01 10:38:43 2021 +0100 +++ b/eric6/DebugClients/Python/DebugClientBase.py Tue Mar 02 17:12:08 2021 +0100 @@ -403,10 +403,17 @@ elif method == "RequestEnvironment": for key, value in params["environment"].items(): if key.endswith("+"): - if key[:-1] in os.environ: - os.environ[key[:-1]] += value + # append to the key + key = key[:-1] + if key in os.environ: + os.environ[key] += value else: - os.environ[key[:-1]] = value + os.environ[key] = value + elif key.endswith("-"): + # delete the key if it exists + key = key[:-1] + if key in os.environ: + del os.environ[key] else: os.environ[key] = value