Multiselect lookup readonly is fixed
With the new codex release (1.9.1), a fix for a bug related to multiselect-lookup allows us now to use readonly instead of disabled to prevent users from editing sampling per wiki when the experiment is already activated. We used disabled because readonly mode allowed to remove items because of that bug.
https://gerrit.wikimedia.org/r/plugins/gitiles/design/codex/+/refs/tags/v1.19.1/CHANGELOG.md