Soft Maximum - best free downloads
dropdown treeview

AlterSourcing DropDown Control
... controls including auto-complete tool, drop-down treeview, grid, tabbed dialog, etc ...

FlyGrid.Net
... can be used as a faster and more convenient replacement of TreeView and ListView (details mode) control. FlyGrid.Net Column component has four types of editor styles - simple, dropdown, dialog and spin, and allows images in column headers and sorting ...

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