Does that page show diagram content loaded from a file? LinkCrossings is serialized with other diagram properties in files, so if you load an old one where it wasn't set to Arcs, you might be losing the value set from initialization code. You could reset LinkCrossings each time after loading a file if you treat it as per-application setting, or may be when applying the layout:

swimlaneLayout.Arrange(thisPage);
thisPage.LinkCrossings = LinkCrossings.Arcs; 

I hope that helps,
Stoyan

Hi,

Check if you haven't set the DrawCrossings property of individual links to false by some chance. If you have switched MeasureUnit to a smaller unit such as Document or Pixel, try setting larger CrossingRadius value.

I hope that helps,
Stoyan