Tag Source defaults to track 1

I am hoping you can help and tell me what I am doing wrong.
I select a track, then click tag source and select Music Brianz, I look up the Album and Artist find the album and then click on the track in the tracks box and it shows the correct one in the metadata box but when I click Ok it changes it to track 1.
What am I doing wrong
Thank you

You have to align the file in the right list with the data on the left.
Use the arrow buttons to move the file until it matches with the data.

Thank you, its so simple.