DockContentDragFilter.StartDrag Method

public void StartDrag(VitNX_DockContent content)
 {
     _regionDropAreas = new Dictionary<VitNX_DockRegion,
         DockDropArea>();
     _groupDropAreas = new Dictionary<VitNX_DockGroup,
         DockDropCollection>();
     foreach (var region in _dockPanel.Regions.Values)
     {
         if (region.DockArea == VitNX_DockArea.Document)
             continue;
         if (region.Visible)
         {
             foreach (var group in region.Groups)
             {
                 var collection = new DockDropCollection(_dockPanel, group);
                 _groupDropAreas.Add(group, collection);
             }
         }
         else
         {
             var area = new DockDropArea(_dockPanel, region);
             _regionDropAreas.Add(region, area);
         }
     }
     _dragContent = content;
     _isDragging = true;
 }