Is there a GoXam equivalent to the GoBalloon shape in the GoDiagram WinForms product? Basically, a callout based shape that can be anchored to another node. I’m not seeing one. I suppose I could use the Callout control from the Microsoft Expression Blend SDK, but it’s not clear to me how I could get the point of the stem to anchor to a given spot.
You could try using custom DataTemplates for “Comment” category nodes and “Comment” category links. You can see the very simple templates that they have by default in GenericWPF.xaml (or GenericSilverlight.xaml) in the docs subdirectory.
But there’s no reason that you couldn’t make them fancier. You should be able to make a nice “Comment” Node DataTemplate pretty easily.
The “Comment” Link DataTemplate is harder. One possibility is to use a filled triangular shape as the implementation, rather than the standard open polyline. You can do this by setting LinkPanel.Implementation to a value other than “Path” – probably you want to use “Stretch”. And you probably would want “Comment” links to be in a background layer relative to the “Comment” nodes, so that the base of the triangle could be entirely behind the balloon/callout body of the node.