FileTreeComponent::setSelectedFile does not look like it could ever work. The target file is passed in correctly, but then it looks through a list of selected files and if it matches one it selects it else it deselects them all. I would have thought it should select the target file whether it was selected or not and if not found, then deselect everything.
I notice your listnox has the following elements:
a. Outline colour and size
b. item click and double click (which is in the TreeView component)
c. item delete key pressed and return key pressed
d. setselecteditem also works.
I would think that your treeview component and all other components of that nature should all have consistent capabilities. I certainly could use it for a consistent look and feel to my VST panels. It would also be nice if labels also had the outline capability so it could be used to further consistent look and feel.
I am using Ctrlr, so I realise some issue could be caused by that, but I believe the issues I have identified here are at the JULES class level rather than the Ctrlr level as I have looked at the documentation and the source code I have downloaded and it appears to have the same limitations.