Lightroom :: Moving Images In Library Collections

I am ruhnning Windows &7 Pro, 64 bit and I'm experiencing inconsistent behavior in Lightroom 3.5 with regard to moving images within collections.  When I try to move an image, to place it in the order in which I would like view the sequence, the image is placed at the end of the sequence no matter where I place it initially.  I've tried the filmstrip view and the grid view and it happens in both.  I recall doing this without problems previously however it was in the imported Library not a collection, but why would this be different??  One still needs to reorder images in collections.  I've made certian to change the "sort" option to user each time I've tried to do this.