Symptoms
List View toolbar buttons aren't draggable when created in the initial wizard, but are when generated via 'Create Labels and Controls'.
Diagnoses
List View toolbar button DIV elements that were created by the initial wizard don't receive the 'draggable' class. Adding this class allows them to be dragged.
Resolution
Workaround: Open up your browser's Developer Console (F12) and copy/paste the following jQuery script into the console:
$('div[controltype="ToolBarButton"]').addClass('draggable')