FlowChart.NET version 6.4.2 contains several customer-requested features and improvements -

Fluent API
Extension methods in MindFusion.Diagramming.Fluent and MindFusion.Diagramming.Layout.Fluent namespaces add support for fluent programming style:

using MindFusion.Diagramming.Fluent;
using MindFusion.Diagramming.Layout.Fluent;
//...

diagram.Factory
	.CreateShapeNode(10, 10, 20, 20)
		.Brush(Color.LightGray)
		.Font("Arial", 12)
		.EnableStyledText(true)
		.Text("Task <i>1</i>")
		.ToolTip("This is the task");

new TreeLayout()
	.LevelDistance(20)
	.NodeDistance(20)
	.LinkStyle(TreeLayoutLinkType.Cascading3)
	.Arrange(diagram); 

DiagramLink improvements
~ the component no longer keeps a separate segmentCount field, removing a common source of errors. The SegmentCount property now calculates its value from ControlPoints elements. The UpdateFromPoints(updateGroups, updateSegments) overload has been removed too;
~ SegmentCount setter no longer refuses changing number of segments if auto-routing is enabled or the link is a self-loop;
~ the new Spline element of LinkShape enumeration draws links as interpolating splines that pass through all of their control points:


Miscellaneous
~ the ModifierKeyAction.ExtendSelection mode selects items within the lasso without deselecting old ones;
~ the Visio Stencils import API provides access to BeginArrow and EndArrow values;
~ The Visio Stencils import API provides access to Connection elements defined for a shape;
~ it is now enough to set EnableStyledText to enable styled-text mode without having to also enable PolygonalTextLayout;
~ fixed bug where ItemAdded event wasn't raised for interactively drawn items;
~ miscellaneous UI control assemblies (NodeListView, LayerListView, Ruler, etc) have been merged into a single MindFusion.Diagramming.WinForms.Controls.dll;

If anyone is interested in trying the beta version, please download this archive containing updated assembly files:
https://mindfusion.eu/_beta/diagram.winforms.642.zip

Any comments, questions and general feedback are welcome.