I have a TreeViewer with an ILazyTreeContentProvider. I want to control the expansion of the top-level tree items: Initially they are unexpanded, but when an Action "Expand" is selected, the item should be expanded.
In the action.run() I currently do
final EntityTreeNode projectNode = (EntityTreeNode) ((ITreeSelection)
// notify the content provider that the node should be expanded; it creates child nodes
// and updates the child count and calls viewer.setChildCount
But the node is not expanded. It should at least change it's icon to show that it has children..