Dockit.Xwt
2 free Wxt Widgets which build&work under MacOs/MonoDevelop/Windows10-VisualStio:
-DockPanel Docking-widget for the Xwt framework.
-PropertyGrid like the System.Window.Forms.PropertyGrid, but then for xwt.
Docking.Xwt supports for now all Xwt's layout engines except GTK3.