"New empty tab" must set focus to input edit widgets

Currently, if focus was inside html page, and "File - New tab" is invoked, focus remains inside html browser with empty page, while it's more useful to set focus to input fields - e. g., if "Index" pane is active, than set focus to "Look at" input field, etc. Since many panes can be visible simultaneously, there can be predefined order to check them, or use last used pane.