I've had these ideas in mind for a long time, but have been spurred into posting action by the discussion in this thread:
https://getmusicbee.com/forum/index.php?topic=36890.0In short, if I had to highlight any one feature that sets MusicBee apart from other music managers and players, it's the use of virtual tags to provide great amounts of flexibility in how tracks are presented without needing to explicity store all those values in real tags. But as you start diving deeper into what's possible, it becomes increasingly difficult to create and maintain them.
In this thread I'm suggesting a few enhancements to make this easier. Other users may also have had similar ideas they want to contribute.
(btw, I've deliberately used a simpler example to better illustrate my suggestions - you don't have to look far on the forum to find people using some truly convoluted virtual tags that would benefit more greatly)
1. Colour-coded bracket matchingHere is relatively simple tag I use to group different types of album:

This the same tag shown in VS Code, with syntax highlighting set to Visual Basic (which works pretty well for virtual tag highlighting):

It would be nice if the virtual tag
Template Editor in MusicBee could highlight opening and closing pairs of parentheses with alternating colours in the same way to make it easier to diagnose issues with nested functions. VS Code also highlights strings and other characters, but I don't see that being as important in MusicBee tags unless it is easily implemented.
(Bonus points awarded though if it is possible to also highlight the parenthesis that matches the cursor position, like VS Code does by drawing little boxes around them.)
2. Preserve white space in virtual tagsCurrently, MusicBee will accept tags with arbitrary whitespace in them, but will remove it when the tags are saved.
Again in VS Code, this is the same formula with whitespace and carriage returns added to better illustrate each of the responses to the different conditional statements:

With or without the syntax highlighting, it would be great if MusicBee saved that whitespace and displayed it again when the tag is edited.
3. Use only displayed tracks in the Template Editor Preview listWhen I'm updating virtual tags I'm almost always looking at a list of tracks that isn't displayed the way I want it to be.
The
Preview list in the virtual tag
Template Editor is helpful to check if a virtual tag shows the intended result, but it always shows every track in the library, which makes finding the ones I'm interested in almost impossible.
It would be more useful if the list only included the tracks that are currently displayed in the main panel - which probably already shows the tracks users are trying to fix values for. Users could still have it display all tracks in their library if they needed that.
4. Resizable windowsMake the
New Custom Tag Definition dialog and
Template Editor windows resizable.