Inserting Track Length on the Tag Panel


I have a problem that is driving my crazy. I am trying to insert the track length in my tag panel but it will not populate.

Apparently, at some point, in order to get Track Length in my columns, I had to create a customized column with the following values:
Sort by=%_length_seconds%
I''m not sure why I had to set it up like that. I did this over 6 years ago. But I had to do it this way. I tried to change back to using the default values of %length% and nothing populates to those fields. The original tracks are FLAC.

However, when I try to create a custom field in the tag panel, it does not work. I put in LENGTH or _LENGTH in the Field but nothing populates. I have tried to research this but can't find an answer.

How do I place the track length into the tag panel?

Any help would be greatly appreciated! Thanks.

If I execute a tag > Tag script, with
Format string: %_length%
Then the Tag Panel Field will populate, so obviously, there is a value being assigned to %_length% in Vorbis Comments. I do not see a custom Tag Map that I may have set up with those fields. So the question is how to get the Tag Panel to use _LENGTH instead of LENGTH for the field but it is not in the drop down and it does not work if I manually add it as %_Length% or _LENGTH.

You cannot add a property to the tag panel that starts with an underscore (with the exception of the path). The variables starting with an underscore usually describe properties that cannot be changed by MP3tag and have informational character.

This is a user-defined field that you can edit any way you want and that, if you really edit it, does not show the real length any more. The only reliable information is stored in _LENGTH.

I understand but I cannot get the information for _LENGTH to show in the tag panel. I tried to create a custom field in the Tag Panel:
Field: _LENGTH
Name: Length
Default value:

But nothing propagates to that field. It is really weird.

Like I said, if I run a tag to tag script with LENGTH = %_length%, the information does get propagated to LENGTH, and thereafter, I can use LENGTH to create a custom Field in the Tag Panel, and everything work. But I should not have to run the script. I should not have to propagate everything from _LENGTH to LENGTH in order to get the information to show in the Tag Panel. IF the information exists in _LENGTH, then the Tag Panel should be able to use _LENGTH to show me the time of the track but, for some reason, it does not.

Really scratching my head on this one.

You cannot modify informational fields.
If you use

then you address the read-only informational property that has been written during the creation of the audio part. You cannot add this information to the tag panel.
You can only add fields to the tag panel that can be modified.
Or in another way: the tag panel does not show other fields than the extended tags dialogue. And the extended tags dialogue also does not show the length or any other property that gets addressed by field variables starting with an underscore.

OK. Seems like something I might suggest for development. If you can set up the columns, you should be able to place it, and have it work, in the tag panel. I will just use my work around.

I am not so sure that the tag panel should show everything that the files list shows.
E.g. as you can set Format Strings as Value for a column, you can enter condition statements that indicate some kind of status e.g. if the field LENGTH is present although it has no relevance.
So each of the displays has a special focus on the data.
The tag panel has its virtues to set the same data for numerous files in one go with the additional support that you can select data from the dropdown lists - something the extended tags dialogue does not offer.
You cannot set the _LENGTH, though.