[KevinH]

We may have inadvertently broken something with the changes to prevent double-loading.

And we will need to better store the last location when changing to another tab so that Preview will always be up to date.

I can look into that on Tuesday. I am tied up tomorrow.

Edit:

Actually, I took a look on macOS and I can not recreate what you are seeing.
The location Preview moves to is just not centred on the PV window but instead is placed at the top of the screen.

If I return to that tab (not the css tab) clicking on that line at the top of the Preview Window
brings me back to the exact same place in CV.

At least that is what I am seeing on macOS.