Examples of good UI for selecting multiple records

Question

I\'m currently revisiting an area of my Windows-based software and looking at changing the relationship from 1->M to M->M. As a result, I need to adjust the UI to accommodate se

Answer 1

self-explanatory GUI http://img25.imageshack.us/img25/8568/28666917.png

Link to the original image

Another thing is, that in my opinion your problem is not about selecting multiple records, but filtering those tens of thousands of records. M->M association can be implemented in variety of way, but the tricky part is to provide a convenient and logical way to browse/search the huge amount of data.