What does this Photoshop message mean?

[PeterAit]

I have opened a JPG image in PS and tried to make a rectangular selection, and get this message. What does it mean? It's just a garden-variety JPG with only the background layer. Thanks.

[digitaldog]

Issue with your Feature settings for some tools that allow this. You're asking for something that isn't possible due to said settings.
Set feather to say zero, try again.

[PeterAit]

Issue with your Feature settings for some tools that allow this. You're asking for something that isn't possible due to said settings.
Set feather to say zero, try again.

Thanks--the feathering seems to have been the issue.

[Simon J.A. Simpson]

Always a problem when the chickens get into the computer…

[Lessbones]

what this really is is a warning that you are not going to see the normal dashed line indicating the areas you have selected.  If you have a layer or mask set at some very low opacity, and you cmd-click that layer to select the content, you will get this message.  However you ARE still affecting those pixels, it's just not showing you an indicator line.  So it's not exactly that it's "not possible" per se, but it's letting you know not to expect the normal indication of what you are currently working on.

[digitaldog]

So it's not exactly that it's "not possible" per se, but it's letting you know not to expect the normal indication of what you are currently working on.

What's not possible is what the dialog tells you. No pixels are more than 50% selected. It would be helpful if it told the user: try setting the feathering to a lower number setting.
Well explained (with Elements, same story) around the 2:30 minute mark here:
https://www.youtube.com/watch?v=Mlsgt_fIgx0
The feather is larger than the rectangle being made; no pixels are more than 50% selected due to that size/feather.