Diptrace allows you to add as many custom fields as you want to the libraries. This could be an extremely useful function, but each time you download a new version with upgraded libraries, all the additional fields are obviously lost.

I dream of a sort of "merge" function that allow you to get additional fields from a library and copy them to another library - provided both have components with the same name.

I second this suggestion and would like to build on it. It would be great if the software were more closely tied into updated libraries. So instead of manually having to go out and download and replace the libraries, they should be updatable from within the application. Think of how virus scan programs download new definitions automatically. Of course there would be the issues of when the user edits the libraries in which case they should be prompted as to what overwrites what while syncing.

Perhaps any user made changes should be done in a protected space, but with the option for that user to submit their custom library parts with diptrace for review and possible inclusion in the general or standard libraries for other users to benefit.