Here's the root of the confusion:

http://helpx.adobe.com/creative-suite/kb/troubleshoot-application-fram e-document-window.html

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The Application Frame is a new feature for Mac CS4 applications that use OWL. The concept is similar to the way that application windows function on Windows operating systems. It enables document windows to move with the application, and supports new features like resize-able N-up window configurations. Because this is very different than the way Mac application windows traditionally operate, it is turned off by default. When turned on, it can produce some confusion, especially when working in a mixture of tabbed document windows, which are children of the application window, and floating windows, which sit above (and sometimes below) the application window. If at any time, your document windows seem to disappear, or are in some other way not accessible, use one of the Arrange commands from the Window menu, such as Consolidate All Windows, Tile, or Cascade.

Please see also post 26, sentence 2, word 4. 

-Noel

I have "seen the light" for quite a bit longer than this thread.  I know exactly what we are and have been talking about, referencing post #2 as proof. 

I realized back about eleven thousand posts ago that this is just a foray into the finer points of terminology, and that we all occasionally struggle to describe the multidimensional world of computer usage in concise terms.  Adobe picked a name.  It's convenient to use that name.

Please understand that, though I'm no Mac expert, as a career software engineer in general (though I have not worked for Adobe) I have a decent insight into how the engineers who designed this stuff think.  Besides eating, sleeping, and breathing Photoshop, I have designed several operating systems, have a solid working knowledge of Windows, and can find my way around Unix.

In a combination of our terms, given that one can resize the Photoshop Main Window when Application Frame "mode" is selected on a Mac, under certain conditions having done so (in possible pursuit of a goal that can better be accomplished in another way) can cause unexpected things to happen.

-Noel

And just to make sure this is clear:  I never use the Application Frame mode myself nor would I ever recommend it to a Mac user under any circumstances.  And, yes, not knowing what it does can throw a user into all kinds of grief, such as the one that gave rise to this thread.