When one moves a node/subtree today one can search only within the current level displayed in the bottom pane.

It would useful if one could search the full tree, or at least search the full tree once one has selected a list on the bottom pane. I am saying this mostly to avoid having to navigate the tree with the arrow keys to find the target.

As you can imagine I am taking the idea from emacs org-mode refile command. Refile works by defining how many levels down the tree the system should search for targets, maybe this would be necessary for the implementation. Probably one would need a breadcrumb on the target search results as there may be more than one node with the same name in one list, but maybe that is necessary only for the selected item on the dialog.

I am not sure I've explained clearly what the request is, but if I did then vote for it :)