The paginated users and messages lists interpolate the pre-encoded filter
query (url.Values.Encode) after the "?" in their pager and CSV-export links.
There html/template treats it as a single query value and percent-encodes the
structural "=" and "&" again, so "kind=robots" rendered as "kind%3drobots" and
the multi-pair message filter collapsed -- every page step dropped the active
filter.
Type FilterQuery as template.URL so the already-escaped fragment is emitted
verbatim (the attribute-level "&" -> "&" stays correct, the browser decodes
it back). It is safe because url.Values.Encode output is strictly
percent-encoded. games/complaints use status={{.Status}} -- a single value in
proper query-value context -- and were never affected.
Ilia Denisov