bblackmoor

+1000. Yes please I would like to see this too.

You might be technically correct re: intention, though I wouldn't say omission in the help docs is an indicator; they're pretty sparse in places. (However, I'm happy to see that the help docs are improving.)
I think we can agree that Serif started with Adobe's platform as, shall we say, inspiration. Understandable as they have dominated the space literally for decades, and for good reason—confiscatory rental model notwithstanding. Serif has made it clear that they're not trying to directly copy anyone, and in many cases the Affinity suite offers the same or even better functionality. There are, however, instances where they deviate from UI "norms" that have existed for many years in ways that don't make sense (to many of us), and hurt the workflow. To me, this is the case here.
 
In Affinity when adding to/subtracting from a selection, it's identical to Photoshop: The cursor coordinates are updated in real time*, as is the width and height of the new selection. The difference is in Affinity, when you release the mouse, nothing is shown. In Photoshop, the updated dimensions of the selection are shown. Again, to me, this is logical: Why would you not show the dimensions of a selection in the Info panel?
Also, I may be missing your point or expectation, but in my work in design and publishing over quite a few years, I've never added to or subtracted from a selection using the Info panel. Maybe there's a great use case that hasn't gotten through my thick skull.
FWIW, my point in commenting here was to agree with the validity of the original post, not to bash Serif. I have great respect for the leadership, the team, the work they have done and continue to do, and the very solid software they've built. To their credit, they do listen and respond.
* On my Windows 11 system (11th gen i7/16gb RAM), there is a noticeable lag updating the info while dragging.

@bblackmoor’s request is valid and logical.
My $0.02: Like many others, I use two monitors. My 'Studio' has all of the panels I use arranged carefully on the second monitor, and my document(s) on the main monitor. I have worked this way for many years; can't stand it otherwise. With all of my panels always open/visible, this issue is not a big deal for me. In fact, I was so accustomed to seeing the selection dimensions in the Transform panel, I wasn't even aware it didn't show up in the Info panel.
But ... if/when you're not on multiple monitors (laptop, iPad...), and you keep the Info panel visible, not having a selection's dimensions there makes zero sense. It clearly knows what dimensions are—it shows them while you're dragging a marquee selection—yet they disappear when you release the mouse. The fact that the Info panel shows a glaringly-blank W: -- and H: -- while there is still a selection seems to demonstrate, rather clearly, that it's not working as intended and expected. The Affinity Info panel is designed to function like the Adobe Info panel which, logically, shows the dimensions of a selection.
Given that the 'functionality' exists in the Transform panel may make this issue less than urgent to fix, but it is an issue nonetheless, IMHO. Hopefully this particular 'little thing' will get addressed soon; it sure seems like 'low-hanging fruit.'
If you've read anything I've posted before, you know I'm a huge fan of Serif for building the Affinity Suite as an alternative to the abhorrent practice of software rental. And the suite has come a long way over the last 18-24 months. However, there are a number of 'little things' and missing basics that detract from the otherwise-good experience, especially for the professionals that Serif is targeting and needs to continue to grow. And I think we all want that.

When making selections by dragging with the Rectangular Marquee tool (or any other selection tool) please retain the width and height values (W and H fields) in the Info panel after releasing the mouse.

P.S. I know you can see the width and height in the Transform panel but it would help to see this in the Info panel too. Currently, the width and height values in the Info panel are well nigh useless since these values disappear when you release the mouse button after dragging a selection.

Respectfully, this is a request/suggestion for desired functionality, not an inquiry into intended functionality.
Here is an example of the functionality I would like added, as shown in a competitor's application (which is what I am currently using).
 

Windows 10 is probably the last Microsoft OS I will install. The adware and spyware in 11+ is too much for me.
Counting software I use, Affinity (and one other piece of software) are the only remaining holdouts without native Linux versions. How the tides have changed!
+1 for official Linux support.

I don't think you get to decide what's "useless", Ronny: particularly when the point being made - that we can apparently expect more from a pretty grim piece of Open Source software than we can from a supposedly cutting-edge, customer-focused commercial solution - is precisely to the point.

I already emailed them for a refund. I don't have time for this hot mess of a software release. 
I will continue to use Affinity photo one like I have been for years. I set it up with DXOPhotolab2 to DXOPhotolab5 for dxophotolab to send the TIIF file to Affinity photo, as others have done the same with DXO or LR. It was a one time set it and forget it process. 
Affinity or any other software company is not paying me to do software fixes for them. I do photography. 
If your product is flaky I will not use it. 

I had no problem installing V2 on my Win 10 pro PC but I wasn't given the choice of where to install it so I assumed it would upgrade V1 at that location. It didn't so I'm now left with both versions, V2 on the windows SSD whereas all my other apps are on a separate SSD. Anyone know how to get V2 where I want it?

I have windows 10 pro, msix files are not associated with any program. Do I have to download any special application from the Microsoft store? do I have to edit the windows registry additionally? is this the only way to do it?