As I read that there is a new info field %_tool% I wanted to try it.
I created a new column with the value %_tool% but a value showed only for the file that was currently the selected.
All the other files had no data in this new column - not until I moved the selection to another file.
F5 re-read the files, but the column with %_tool% remained empty for those files that had not been selected yet.
I had the library switched on during these attempts.
So I switches the library off which leads to a restart of MP3tag, the files were read again - still no display in the column tool, not until the file was selected.
My expectation would be that any rereading of files would also reread the data for "tool" and not when the file gets the focus.
Only Ctrl-T got the data (Lame3.99r in this case)