A question raised many times is filtering a gallery from a multi-choice combo box on a multi-choice field. This is a many-to-many filter. Depending on the data source, this may not be Delegable as the in operator is necessary, and also ForAll and Ungroup have lesser but existing limitations.
A gallery can be presented with a single filter searching for any item selected in the Combo Box existing in any of the values contained in the multi-choice field in the data source.
To do this, the ForAll() operator is needed to create a Table filtering the data source field for each of the selected values. This process results in a series of records that are themselves Tables with a single field Value, so Ungroup() is used to resolve the final list.
Also, allowance has been made for no entry in the Combo Box.
If( Len(ComboBoxName.Selected.Value) = 0, DataSource, Ungroup( ForAll( ComboBoxName.SelectedItems As aSel, Filter( DataSource, aSel.Value in MultiChoiceField.Value ) ), "Value" ) )