Show specific Folder(s)

Many times we want to load a big set of media files to memory and then start processing by album (one at a time). But selection is always a pain (we want to filter out everything but one album at a time).
I think I have found a good approach so developer(s) can satisfy this request. Prerequisite is that all albums are placed on a separate folder of course.

Program always knows the list of folders already loaded to memory because we select, no matter how, specific folders.
So the list of involved folders it is already available (list of %_directory% info from each media file).
E.g.
C:......\Artist 1\Album 1\CD 1\Trackxx.
C:......\Artist 1\Album 1\CD 2\Trackxx.
C:......\Artist 1\Album 2\Trackxx.
C:......\Artist 1\Album 3\Trackxx.
C:......\Artist 2\Album 1\CD 1\Trackxx.

The list of folders involved is as below (let's include all super folders to cover all requirements):
C:...
C:......
C:......\Artist 1
C:......\Artist 1\Album 1
C:......\Artist 1\Album 1\CD 1
C:......\Artist 1\Album 1\CD 2
C:......\Artist 1\Album 2
C:......\Artist 1\Album 3
C:......\Artist 2
C:......\Artist 2\Album 1
C:......\Artist 2\Album 1\CD 1

If we display this list in a dropdown field (like the tags on the left side) it can be easily used as filter (new feature). I assume the (automatic) internal filter would be of something like %_directory% starts with %selected_folder%.

To make it more user friendly, the common beginning part of all folders can be omitted from the dropdown list (for long folder path).
In above example Foldernames displayed would start as of Artist level. Two (Next, Previous) buttons can be placed next to this dropdown to make a smooth navigation.

Please share your opinions.

There has been a similar idea in 2011 ...
see Suggestion: Collapse-able folders

I remember this post. It is very nice to have but I think mp3tag developers have their "technical" reasons for not implementing it. I mean it must have some showstopper or really needs to restructure the whole program, who knows.
My point is to bring a request can be implemented with small impact to existing program.
So in fact this is a kind of simplified filter: User is provided the list of loaded media folders (and also their parents) and he choses one. That would be the same like applying manually the filter %_directory% starts with <selected_folder>.
Looks feasible to me.
Well, someone may say I need the same for other tags. We have to think for a generic solution too but later.

Load all files from all folders you want.
If you need only one folder in list view, then apply the Mp3tag tool "Load this folder in Mp3tag" against one file.

This tool is defined as ..
Name: Load this &folder in Mp3tag
Path: Mp3tag.exe
Parameter: '/fp:"'%_folderpath%'"'

Switch back using the button ...
"Change directory ..." or "Favorite directory"

DD.20140923.1751.CEST

There are many workarounds, I know. ALT+TAB, Backspace to go one level, arrows to select another folder, ENTER, Shift+F12 (and 3 to open it in mp3tag).
I started the thread because I see added value with this feature.
I would like to know if mp3tag users agree with this idea or not (and why).

The flaw in the "special folder" approach is that it favours one particular workflow and it has a lot of pre-conditions to work its miracles.
It relies on a folder structure that in other workflows is actually the result, the last step esp. if the folder structure is generated from the tag information.
So I think that the alternative workflow could be that you have a dump folder where you put all files that need tagging and you do your work.
And after that you move them to the correct location.
E.g. Windows Media Player has a set of watched folders. It is very annoying to get the "locked file" message because you manipulate files in folders that WMP watches". It is nicer to have a corner in the file system where you can work unmolested.

And if you have files scattered across the file system as you once had the idea to store files for "The Beatles" (letter T at the beginning") and now it is just "Beatles" any grouping or filtering based on full folder names would make work much harder. The filter for parts of the fully qualified filename is already implemented.
And as there are many more workarounds (which I would call workflow approaches) it should be possible to live without the need to create a completely new GUI for this one workflow, esp. if it can be emulated so that all parties have the freedom to use MP3tag the way they want it.

OK, OK. I don't intend to "fight"for this feature. It is only a nice to have.
There are much more important things like suggestion nr 4 in this this thread.