Enforce valid user interaction in arrange panel.

Added disabling of SIP arrange panel action buttons when the user has
highlighted an item that the action should not apply to (creating
directories within files, for example).
Minor CSS tweak to SIP arrange paging links.
Cleanup/enforce valid user interaction.

Added logic to disable action buttons in the SIP arrange
panel when conditions for the action are unsuitable.
Commented and cleaned up JavaScript.
Fixed issue with file explorer ad-hoc properties.

Fixed an issue where if ad-hoc properties aren't found, it caused an
error.
Auto-search transfer backlog in originals panel.

If a open opens the originals file browser and the transfer backlog isn't
yet searched, trigger a search.