Dialog auto focus does not check for hidden tabs.

[Joe Kavanagh]

When determining whether initial dialog focus should be on the first tab, dialog._.tabIdList.length is checked to see if the dialog has more then one tab. This will not take into consideration any tabs that are hidden. When a dialog has all but one tab hidden, and keyboard navigation is used, the dialog will not receive focus if CKEDITOR.config.dialog_startupFocusTab is set to true. Focus will remain on the toolbar.

The if statement is located in the CKEDITOR.dialog constructor in a dialog 'show' event listener, which is used to setup focus:

if ( editor.config.dialog_startupFocusTab
	&& me._.tabIdList.length > 1 )

could be changed to:

if ( editor.config.dialog_startupFocusTab
	&& me._.pageCount > 1 )

pageCount only gets incremented if the tab is not hidden.