I typically open the Tag Panel using the Ctrl-Q shortcut, with multiple items selected in the grid. If I close the Tag Panel using that same keyboard shortcut, cursor focus is properly repositioned to the selected grid items.
If I click the upper-right cross-icon button to close the Tag Panel, however, cursor focus is not returned, forcing me to re-select the grid items to carry on editing them. Actions such as the autonumbering wizard refuse to work until you re-select the items (or until you tap Ctrl-Q twice to re-establish item selection).
Not the biggest issue ever, but a bit of a nuissance all the same - and one that's been persisting for multiple consecutive versions now.
Keep up the great work - love mp3tag!