The pagetree files needs to be refactored to be more generic. Mainly this is the context menu implementation, the tree implementation and their related components like the node user interface, the tree editor and the state provider. The same would be needed for the top panel and the deletion drop zone, but they need much more changes to be really generic.
I don't will do that for 4.5 anymore and it will be a task for 4.6 as the changes are much to huge. The goal for 4.5 was to create a stable pagetree. Sorry!
(issue imported from #M17154)