What's Changed
Filter Expression
While it's quite common to filter the parent entries in the drop down of the relation reference widget, in the relation editor one needed to enter the filter manually every time when linking children.
With this QGIS implementation one can configure a filter expression (with the scope of the target layer) on the relation editor configuration and you will have the linking dialog filtered qgis/QGIS#58448
Especially on Linking Relation Editor this makes sense, so it's implemented here as well.
leads to
This feature is only available when using QGIS >= 3.40 but this release has no issues with lower version (just no filter)...
Sponsors
This feature has been made possible through the financial support of Canton of Solothurn