Yes, but for all labels as well. What label where is used. The cross reference is great for fast browsing in big projects. As Tomasz already said, FASM supports only bit used/not used.
I hope in the future there will be full featured cross reference as well.

Since I am generating FASM code -- it will be easy for me, just an option.

Please try my quick 1.69.43 development release. I added additional table to .fas file (the header is expanded to 64 bytes, nice size, the offset of new table is at 56, and its size at 60). The table contains 8-byte entries, first dword is an offset in symbols table, second dword is an offset in assembly dump. If symbol was used many times in the same line, there will be duplicates in the dump; if symbol was used in line inside "repeat" block, the references will link to different places in assembly dump, which in turn will link to one and the same line in source.

Please let me know if that works for you.

Hey, it is great! I will test it and use it ASAP. Thanks!