JDiagram version 4.0.1 adds various customer-requested features and fixes several bugs:

Preserve order in tree layout
The Balance property of TreeLayout can be set to Preserve to keep the original geometric order of child nodes when arranging them under their parent. This can be used to arrange tree branches in a specific order by first placing them in increasing horizontal or vertical positions. Another possibility is to apply TreeLayout from nodeModified handler to let users rearrange the tree branches by dragging and dropping a node.

Undirected path finding
PathFinder now supports undirected mode. Its methods have been changed from static to instance, and its constructor takes an ignoreDirection parameter. If ignoreDirection is enabled, the underlying graph is treated as undirected and link direction is not considered when looking for paths.

Selection improvements
~ DiagramView.Behavior can be set to SelectOnly to let users select existing items, but not modify them or draw new ones.
~ The SetsDirtyFlag property of the Selection class specified whether the Dirty flag should be set when selection changes.

Miscellaneous
~ Style classes now contain a FontUnit property specifying the unit of measure of FontSize. Important: the default FontUnit value is Point, while font sizes were always measured in diagram's MeasureUnit in previous versions. If using styles instead of setting items' Font property, when upgrading to version 4.0.1 you must either adjust FontSize for the Point units, or change FontUnit to World, which makes it compatible with previous versions.
~ The last row in a TableNode will now be rendered clipped if it fits only partially inside the node, whereas in previous versions the row would not be rendered at all.
~ The HandlesStyle of a link can now be set to Invisible to stop rendering its selection handles, but still allow dragging control points.
~ The AllowAddChildren and AllowRemoveChildren properties of ContainerNode specify whether users are allowed to add or remove child nodes to / from the container.
~ The getNearestBorderPoint method of DiagramNode can be used to find a point from the node's border closest to a specified point.
~ the Ruler control now raises nodeModified events when nodes are moved using alignment guides.
~ styled text can contain <br> tags to force line breaks.
~ HeadBrush, BaseBrush and IntermediateBrush properties allow setting distinct brushes for respective arrowhead shapes.
~ the Cell.TextPadding property allows customizing text margins of table cells.

Fixed bugs
~ Fixed crash in LayerListView control.
~ table.resizeToFitText did not work correctly with styled text.
~ fixed bug when cloning DashStyle objects.
~ zTop and zBottom methods did not work correctly with layers.

If anyone is interested in trying the beta version, please download this archive containing the updated control jar file:
https://mindfusion.eu/_beta/jdiag401.zip

Any comments, questions and general feedback are welcome.