[datrixlab]

Description

GlancesFilterList.filter appends to the existing list rather than replacing it, so
the property never describes the current filter — each assignment adds to whatever
was already there. Its sibling in the same file, GlancesFilter.filter, replaces.

That matters because both process_focus and export_process_filter are written
twice during a normal startup:

	focus	export
glances.conf	plugins/processlist/__init__.py:254	plugins/processlist/__init__.py:250
command line	processes.py:163 (set_args)	standalone.py:71

The plugin loads the configuration file first, the command line is applied just
after, and is_filtered() ORs the accumulated list. So with

[processlist]
focus=.*firefox.*

glances --process-focus .*python.*

Glances focuses on firefox and python together. The command line can widen the
list set in glances.conf, but never narrow it — while docs/config.rst states:

User-specific options override system-wide options, and options given on
the command line overrides both.

Assigning the whole list restores that precedence: the configuration file is read
first, the command line replaces it. --process-focus a,b still yields both, since
that is one assignment.

Reproduced against develop before the change:

config focus=nginx      -> ['nginx']
--process-focus python  -> ['nginx', 'python']
is_filtered({'name': 'nginx'})  = True     <- command line could not narrow it

Resume

• Bug fix: yes
• New feature: no
• Fixed tickets: none open that I could find

Tests

Added to test_020_filter in tests/test_core.py: assign twice, assert the second
assignment is the whole filter. Verified by reverting glances/filter.py alone — the
new assertions fail with ['.*firefox.*', '.*python.*'] != ['.*python.*'], and every
pre-existing assertion passes both with and without the change.

tests/test_core.py: 48 passed, 6 skipped. The process- and filter-related suites
(test_processes_cache, test_plugin_processcount, test_sort_missing_values,
test_program_aggregation, test_globals, test_glances_stats, test_lazy_views):
115 passed. ruff check clean; ruff format --check reports only a pre-existing
complaint at tests/test_core.py:422, which is present on an unmodified develop.