Fix project panel selection related issues

[KristalAlfred]

Small attempt at solving #7003 and #7005.

Selecting as a reaction to actually opening a new item doesn’t seem robust in all cases. I suspect there’s a reason for doing so which is unknown to me, but I tried just going with the naive approach of selecting every time an attempt is made to open an item. To me this felt a little more consistent with how I am used to other editors working, so I'm submitting this PR as a starting point at least. I'd be happy to work more on this with some feedback!

Cheers!