This is Fixed in 4.1.13.1799

I can reproduce: http://www.ventismedia.com/mantis/view.php?id=13321

4.1.11.1783 on Win10Pro-64.

I beg your pardon for not including this information at the very first. :oops:

Respectfully, ITG.

Which version of MediaMonkey?

Oh boy. Y'all don't very much like bug reports on Album Artist tags, if I read bug reports right.
But the issue I uncovered is a bit different than those I see in the existing bug reports.

Note 1: I make HEAVY use of the Album Artist tag. In fact, it is the Album Artist which is the highest level differentiation.
Note 2: Please see the video that shows the problem listed herein.

Scenario: In the central file window, I am editing the blank tags of an audio file, with Album Artist, Album, and Artist the first three fields to be entered, in that order.

1a. I slow double click to open the Album Artist field.
1b. I enter/select a value for Album Artist.
2a. I tab to the Album field.
2b. I enter/select a value for Album.
[i][b]3a. I tab to the Artist field.[/b][/i]
3b. I enter/select a (different) value for Artist.
4a. I press return to complete the tagging.

5a. I notice that [b][b]step 3a clears the Album Artist field[/b][/b] recently edited [i][b]= BUG[/b][/i].
5b. I notice that step 4a enters the Artist field value into the Album Artist field. (Undesirable feature, but not a bug.)

See the video of the bug in action at: [url]https://www.dropbox.com/s/8leud36db4og7qy/MM_TagsBug_20160530n5.mp4?dl=0[/url]