/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name="includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives)
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent<SkeletonRenderer>() will be called as a fallback.
/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name="containsBoundingBoxes">Disables popup results that don't contain bounding box attachments when true.</param>
/// <param name = "includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives).
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent<SkeletonRenderer>() will be called as a fallback.
/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// <param name="includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives)
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent<SkeletonRenderer>() will be called as a fallback.
/// Smart popup menu for Spine Events (Spine.EventData)
/// </summary>
/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name = "includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives).
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent(SkeletonRenderer)() will be called as a fallback.
/// </param>
/// <param name="fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// Smart popup menu for Spine IK Constraints (Spine.IkConstraint)
/// </summary>
/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name = "includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives).
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent(SkeletonRenderer)() will be called as a fallback.
/// </param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// Smart popup menu for Spine Transform Constraints (Spine.TransformConstraint)
/// </summary>
/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name = "includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives).
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent<SkeletonRenderer>() will be called as a fallback.
/// <param name="startsWith">Filters popup results to elements that begin with supplied string.</param>
/// <param name = "includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// <param name = "defaultAsEmptyString">If true, the default choice will be serialized as an empty string.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives)
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent<SkeletonRenderer>() will be called as a fallback.
/// <param name="currentSkinOnly">Filters popup results to only include the current Skin. Only valid when a SkeletonRenderer is the data source.</param>
/// <param name="returnAttachmentPath">Returns a fully qualified path for an Attachment in the format "Skin/Slot/AttachmentName". This path format is only used by the SpineAttachment helper methods like SpineAttachment.GetAttachment and .GetHierarchy. Do not use full path anywhere else in Spine's system.</param>
/// <param name="placeholdersOnly">Filters popup results to exclude attachments that are not children of Skin Placeholders</param>
/// <param name="slotField">If specified, a locally scoped field with the name supplied by in slotField will be used to limit the popup results to children of a named slot</param>
/// <param name="skinField">If specified, a locally scoped field with the name supplied by in skinField will be used to limit the popup results to entries of the named skin</param>
/// <param name="includeNone">If true, the dropdown list will include a "none" option which stored as an empty string.</param>
/// <param name = "fallbackToTextField">If true, and an animation list source can't be found, the field will fall back to a normal text field. If false, it will show an error.</param>
/// <param name="dataField">If specified, a locally scoped field with the name supplied by in dataField will be used to fill the popup results.
/// Valid types are SkeletonDataAsset and SkeletonRenderer (and derivatives)
/// If left empty and the script the attribute is applied to is derived from Component, GetComponent<SkeletonRenderer>() will be called as a fallback.