When switching between similar views (such as Tags and Three Panes) the focus is lost on the item being highlighted in the view. Most of the time, when I switch between similar views, I want to keep the focus on the item that I had been looking at in the first view. Is this behaviour deliberate? If so, what is the advantage of losing the focus?
Tags and Three Panes are not similar views.
There are four views that retain the focus of a selected item when switching between any of the four: Icon, List, Column and Split.
Neither deliberate nor buggy, just a shortcoming. Actually earlier releases didn’t retain the focus and we got requests to change this. We changed the behaviour and got complaints about the new behaviour and therefore changed it again 
I can see @khw’s point – when switching to View as Tags it might be helpful sometimes to have a starting point.
(to Christian’s point – this behavior is maybe a candidate for a hidden preference?)
Arghh!! No more hidden prefs - LOL!!! 
Just my two cents, changing the View is just changing the presentation of the data. It would seem altogether logical to remember the selection when switching between views.
Yeah, maybe that’s one too many.
Or at least when switching from Tags to some other view. It seems that doesn’t happen.
I, for one, don’t want the Tags display to reflect a selection made in another view when I switch to it. I prefer the Tags view to be ‘pristine’ when I switch to it, not having any document/tag(s) already selected.
Well, none of the views are “similar” so it was my wrong choice of word. It just seems illogical and confusing to have 6 views with a subset of 4 that retain the focus and 2 that don’t. Surely they should be either all pristine when switched to, or all retain the focus. My vote would be for retaining the focus for all of them, but that’s just the way I work.
Not quite.
If multiple items are selected in List view they’ll be “semi-selected”, i.e. dimly highlighted without input focus, after switching to Columns view, with no way to regain focus using the keyboard (AFAICT) because Data > Reveal only selects/focuses the “last” item (as I recently questioned). Or, start with a multi-item selection in Columns view then switch to List view and back to Columns view.
Dt selection/focus inconsistencies like this, some which I’ve posted about, are relatively common occurrences for me.