When you are programming buttons dynamically, you might be enabling or disabling buttons that are not in use. For example, a back button can be greyed out and disabled on the first page of a slideshow. If you are leaving these buttons on the stage, and disabling them by button.enabled = false; code, then make sure to also set the button.tabEnabled = false; as well.
Buttons that are disabled, but still tabEnabled, form silent holes in the tab order. You still tab to them, but no yellow focusrect will appear. This might be confusing to users that use the tab key.
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