Fix a possible null pointer dereference
Show unresolved references in red
Do not resolve references during automatic arrangement in PositionLayout
Resolve references when importing test java projects
Extend the default symbol search of Node to also consider SEARCH_DOWN
Add symbol type support for symbol defining nodes.
Make symbol resolution a bit more precise
Fix a bug where old child items would not be deleted on form change
Fix an issue with changing forms in declarative items.

Any existing cursors are now properly deleted when a form is changed.
Add tutorials for creating nodes, visualizations, and handlers