When renaming a file, adjust the selection as well if needed.

Fix for #9225. This also fixes #9294.
Always update scroll information for the file tree so that selection is positioned correctly.

This was a premature optimization avoiding offset computation which is generally expensive.
Rerender on change of focus between working set and file tree
Limit the cases in which previous context is saved to avoid context highlight flashing.
Don't try to open newly created directories.
Signal change in file tree when selectionViewInfo changes.

There is a special case in which we don't signal that change (it's noted in the
code). This should eliminate some cases of inconsistency. A related change is
that setSelection will no longer select items that aren't visible in the tree
(something that does not happen in real life anyhow).

This is a fix for #9343.