Un-supported vs. no-extension files

I do not recall doing anything

I long as I can remember it always was like this for me

That is what also I do: I use listed option from the shell menu to create a TXT file or any other file, be it in Windows Explorer or FreeCommander, name it and remove the extension. Or I can copy any file and rename it to whatever, also without extension. And it will show on the list of files in Mp3tag. But if I re-add to it an extension like MIDI or JPG it will not longer be loaded up; but then I can remove the extension and once more put it on the list

I Was not aware of that option under the

File > Options > Tags > Tags > Restrict Incoming Files to:

What I have there is

*.aac; *.ape; *.apl; *.asf; *.flac; *.mp+; *.mp1; *.mp2; *.mp3; *.mp4; *.m4a; *.m4b; *.mpc; *.ogg; *.ofr; *.ofs; *.spx; *.tta; *.wma; *.wv; *.tak; *.oga; *.flc; *.m4v; *.opus; *.dsf; *.wav; *.wav; *.aif; *.aifc; *.aiff;

And just now I tried adding a fake "*.mp333" format to the list. It stays there but does not allow for loading files in MP333 format [while for example Winamp does allow and even recognizes them as a real MP3 format and plays them]. The same thing happens with a FLAC turned to a fake *.flac2; in that it does not show up in Mp3tag despite of being listed under the Restrict Incoming Files list

I do not keep text in them- they are the text themselves

Those are merely small / quick notes, often written with >>! << in front of them, so that they will be listed [alphabetically] in the beginning top of the file list of a given folder [thus being visible right away upon entering a folder]. And sometimes such a note I put in form of a sub-folder [if there are many normal sub-folders and the files are shown after them - only after scrolling of the view]

For 99% I did not do anything and had the same behavior on Windows XP, as I have now on Windows 7 x64