We have created a tool class that adds connection anchors to containers, with coordinates specified in AnchorPattern.Points using a mix of UnitType.Fixed and UnitType.Percentage. For example, in Horizontal mode, an output anchor could have its Y coordinate 12 Fixed units down from the top of the container, but its X coordinate at 100 Percentage units, to keep it always at the right side of the container even after it is resized. (We then use custom Draw code to render the anchor's appearance slightly outside the container's Bounds, but that is not important for this question.)

We have found that in Vertical mode, with an output anchor X coordinate at 15 Fixed units and a Y coordinate at 100 Percentage units, the anchor will render at the desired position but the mouse will not respect this position. Specifically, the hovering mouse cursor will change from arrow to hand, but dragging will initiate a selection box and not a new connection line. The "hot spot" for initiating a new connection line seems to be far below the actual position of the anchor.

We have tried many experiments: changing the exact coordinates set by AnchorPattern.Points, the values for our class's Bounds, or the behavior of our class's HitTest() and HitTestHandle() callback methods. No matter what we have tried, MindFusion seems to use its own internal logic to determine its cursor change and "hot spot" positions.

Is this a bug in the MindFusion code, because MindFusion is not expecting an anchor to be attached to a container? Or is there some change we can make to our application to get the correct mouse behavior?

Thank you.