When the user selects a tab in a JTabbedPane, the AccessibleState of that tab (specifically the JTabbedPane.Page inner class) will have a new AccessibleState - that of Selected (and the old one will also have a new AccessibleState, this time with Selected no longer a member of it). This should result in the Page inner class object *itself* firing a PropertyChange event of type ACCESSIBLE_STATE_PROPERTY. Instead, incorrectly, the AccessibleJTabbedPane is firing that event.

This bug causes screen magnification software to not correctly magnify the appropriate region of the screen in response to tab selection, as it is supposed to get the bounding rectangle of the object which fires the PropertyChange event and magnify around that. Since the object firing the event is always the AccessibleJTabbedPane itself (and not the Page), magnification fails to track user tab selection.