'Twould be nice if the tab the user has selected could be restored when a dialog box with a tab view is re-presented.
Or is there a way and I'm just brain-dead at the moment?
Use the «value» property of viewFactory:tab_view() with data from «identifier» from nesting viewFactory:tab_view_item(). I just tried this and it works well. You can bind this value directly to entry in preferences table, and the tab selection will be restored at each run.
One small gotcha with this: in Lightroom 3.5 [I can't check earlier versions], tab_view.value is nil until the user has actually selected a tab_view_item. So, you need either to set tab_view.value when constructing the view or to test for nil before using tab_view.value.