I'd really like mp3tag not to evaluate the scripts of out-of-view columns. The processing of in-view columns delays many operations inc. even menu drop-down, and I have columns that (inexplicably) take around 3sec for just 16 files. I'd really like that not to happen when they are out of view, else the only other workaround is to delete them.
Yeah I'd really like to be able to enable/disable columns (i.e. visible/invisible) so that really complex calcs don't need to be made all the time, and without having to delete the columns altogether. When you have many tracks loaded it can take a long time to do anything.