Few beginner questions (not found in the FAQ)

Hi,
I'm new with Mp3tag, and i have few questions and i can't find the answer in the FAQ, probably because these are beginner questions.

I decide to have my original CD in FLAC. So i used EAC (Exact Audio Copy) to put my CDs on flac in my computer.

I filled up the following tag form ( manually, when i didn't knew about Mp3tag )

And then, i put the FLAC song in Winamp, and surprise!! The tag doesn't appear in Winamp, it was written something like: Unknown Artist - Unknown Track
But when i looked in the tag of my .flac file, all was perfect.

This is the time where i found Mp3tag, i tried to fill the tag form via Mp3tag, and, surprise, it's work in Winamp. But strangely, the tag form (like seen in the picture above) appear to be empty.

So my questions are: Why is the tag form appear empty ? (considering that it's working in Winamp)
Is the tag are registered somewhere else in the computer ?

If i put my .FLAC edited by Mp3tag in another computer, is the tag will still appear in Winamp on another computer ? (I looked the size of my .FLAC before and after editing with Mp3tag, and it's still the exact same size).

Last question: I know the .FLAC file need padding to be able to write informations and to add cover artwork. So i know that all that Mp3tag re-write the .FLAC file to add all those information. But is it like re-enconding the file (and possibly lose quality) ? Or is it an exact copy of the flac in which the tag are added ?

Sorry for my beginner questions, but i'm just trying to learn more about "how it's work"

Thank you so much!!

It's empty because Windows doesn't support flac without installing additional software.

Yes.

Only if there is not enough padding the file is rewritten. It's an exact copy. No quality loss.

Thank you dano for answering my questions. With your answer, i know that i like mp3tag because it is like i want.

I wonder which "additional software" is needed for windows xp to be able to "detect" the tag in the "windows tag form".

Try this.