## Problem/Motivation Webform stores every submitted value as a row in webform_submission_data, keyed by (sid, name, property, delta). When you add the default "Contains" string filter to a webform_submission view, it filters on the sid join key rather than the value column, because the table's relationship is not constrained to a single field key. There is no out-of-the-box way to filter a submissions view on the value of one specific element (e.g. "show submissions where postcode contains BN1"), and composite elements (address lookups) store sub-fields as separate property rows, which the default filter cannot target at all. ## Proposed resolution Provide a localgov_forms_submission_data_filter Views string-filter plugin, exposed on the webform_submission table via hook_views_data_alter(). The filter adds its own LEFT JOIN to webform_submission_data with the field key, the property (empty for top-level fields, the sub-field key for composite elements) and an optional webform_id baked into the join conditions, then delegates to the core string filter against the joined value column. Site builders configure Webform field key, optional Sub-field property and optional Webform ID per filter instance; multiple instances can coexist in one view targeting different fields. ## User interface changes New "Webform submission data field (text filter)" filter available when building a view based on Webform submissions.