That trim piece does not make sense how it’s installed. It’s a booger to take out and put back in. Not the best engineering marvel for sure.
Actually, it does if you look at how the interior was installed on the assembly line.
There is an order of installation that all manufacturers follow, with a few variances depending on the year/make/model. i.e. Convertibles, Vettes, British sports cars, etc. (Jags make NO sense.)
There are exceptions even among the various body styles of GMT400's.
But, in general, the basic order of installing an interior is, top/rear > bottom/front. Removal is the opposite.
That large upper rear panel.
The one that most people usually break on their first attempt. It's the very first piece of trim that's installed after the headliner. (Top/rear.)
It's screwed to the body at the ends. But that's hidden by the B-pillar panels.
The B-pillars have tabs that slip in to that first panel, over top of & hiding the screws.
Most people try to remove that upper panel in the same manner as that panel below the rear window. A couple of quick tugs up & out from the bottom edge & it's off.
Nope. Doesn't work that way for that upper.
B-pillars pulled out at the bottom first, then down & out from the top exposing those initially installed screws.
I see so many of those upper trim pieces in the wreckers busted off at the screw tabs.
Don't feel bad, though. You guys aren't the exceptions.