ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / TOCMapPaneProviderPane Class / Secondary Property
Version

Secondary Property (TOCMapPaneProviderPane)
Gets the secondary flag value. Returns true if the pane can be positioned as a secondary pane "under" a Map View.
Syntax
public override bool Secondary {get;}
Remarks
Use DockUnderMapView instead
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also