Swimlanes includes a blank lane which sets field to default

When adding a custom configuration which leverage swim-lanes and a string-based field, it appears that a default "blank" swimlane is created and added at the bottom. Moving a work item to this field *in State* or *cross States* will push it to the pre-set `defaultValue` swimlane if allowed and the item is not already in the Swimlane value equal to `defaultValue`.

Additionally, if a State is marked with `"isBacklog": true`, the swimlanes are not available for that column (I assume because it instead maps to backlog priority?).

Should this blank swimlane exist? If so, can it gain context about the default value that is set when dragging an item here, ex 'Default: ' as the title to avoid confusion when multiple values are present?


````
"swimlanes":{
"field":"Custom.WorkStatus",
"defaultValue": "Active",
"values":[
{
"value":"Active",
"title":"Active"
},
{
"value":"Needs Clarification",
"title":"Needs Clarification"
},
{
"value":"Dependent On Other Work",
"title":"Dependent On Other Work"
},
{
"value":"Branch Not Available",
"title":"Branch Not Available"
},
{
"value":"Other",
"title":"Other"
}
]
}
````

Aucun fichier, test ou point d’entrée n’est identifié dans l’issue. Reproduisez la configuration personnalisée des swim-lanes et examinez la gestion de la lane vide, le comportement de glissement de defaultValue et les états de isBacklog ; terminé signifie que le comportement prévu est établi et que les deux cas signalés sont couverts.

Rédigé par le modèle d'indexation à partir du texte de l'issue.