P: Levels dialog auto options: "snap neutral midtones" state resets when changing algorithms

Thanks ManHew -- I've tested this out and was able to reproduce. Have logged a bug for the team to investigate further. 

Regards,
Pete

Still a bug in 19.1.4

Still a bug in 19.0

I did the update and it still happens on Windows.

The first attempt it does in 2015.1.2. Then, after you've gone through once, turning it back off again each time, it stops turning Snap back on. Or you could update to 2015.5 like I did today. Then it doesn't happen at all, at least not on my Mac.

Just to add another detail for this bug.
If the snap option is on by default and I turn it off before choosing a different algorithm, it actually snaps back on again.

I don't see why you feel it is necessary to defend something that is clearly either a bug or bad interface design, if you want to believe that this is intended.
You can't provide an explanation why the dialog is showing unexpected behavior and try to guess why it it like this. But I'm not interested discussing the issue depending on a lot of guesswork.
Common interface guidelines should be used when creating dialogs and these don't include that a checkbox needs to be reset the first time you choose a different option from a group of radio buttons.

It appears that changing algorithms resets the entire dialog, apart from clipping, of course.

Why "of course"? It makes no sense that some options reset to a fixed default, when others don't.

If you change algorithms, you may not necessarily want to have Snap Neutral Midtones to go along with it, or to affect your view of the algorithm as you try to choose the best setting.

Yes, I want Snap to go along with it. This is why I set it as default. I want to change the algorithms while Snap is on. It also doesn't make sense in a top to bottom scenario. The results of the algorithm with or without snap are wildly different depending on the picture. You cannot choose the algorithm and then the snap option. Sometimes you have to try different combinations.
Overriding a user default, because he "may not" want this, is not acceptable interface design, because he actually "may" want this. Even more so when it is not documented. 

The dialog is inconvenient to use, so I'm pretty sure they didn't intend us to use these settings like presets. I suspect there are a lot of folk who use this feature who would like the options to be saved as presets in addition to the dialog settings for how the Auto feature functions normally.

I don't think the dialog is inconvenient. At the moment I use it often to color correct about 1500 old photos and apart from this bug I don't have a problem with it.
And yes, other dialogs have an option to save multiple presets, but this dialog is relatively simple and multiple presets are probably not needed.

I never use the Auto function, but it's much improved over the years and I understand many find it efficient to use it. So okay, more trial and error. . . Here's what I'm seeing. It does indeed turn off when I reenter the dialog box whether or not I save my setting as a default. It appears that changing algorithms resets the entire dialog, apart from clipping, of course.  Once you determine that for this image, you want the Snap on, it stays on for the 3 algorithms that can use Snap, which I think is the correct behavior.

In my opinion, this is as designed, not a bug. If you change algorithms, you may not necessarily want to have Snap Neutral Midtones to go along with it, or to affect your view of the algorithm as you try to choose the best setting.

So just guessing here, they had to make a choice between affecting your view of the algorithm with the Snap option left on because the last image you viewed, you wanted that,  and you have to turn it off manually if you don't like it, or letting you start fresh each time you choose a different algorithm. I'm guessing they chose work top to bottom in the dialog, affecting the change you want to see as you go.

The dialog is inconvenient to use, so I'm pretty sure they didn't intend us to use these settings like presets. I suspect there are a lot of folk who use this feature who would like the options to be saved as presets in addition to the dialog settings for how the Auto feature functions normally. Perhaps a feature request is in order?

Like I said, I set Snap Neutral Midtones to be on by default and when I change the algorithm it turns it off. If I manually set it on again, it stays on, even when changing algorithms.

Enhance Brightness and Contrast just disables the Snap Neutral Midtones checkbox, but otherwise behaves just like any other algorithm. If the option was manually on, it is on after changing back to one of the top algorithms. If it was on by default and you change the algorithm the first time to Enhance Brightness and Contrast and then back, it is on again.

Just give it a try.