gdm loads the background and then freezes at various points. (panel loading, splash screen loading) Also resets the panel and moves all icons when login works.
Please post the output of emerge --info, the actual gdm version, is this an upgrade from a previous 2.14 gdm, or from 2.12, 2.10, is it a clean install? There should really be more than just a short blurb in a bug report that causes us to guess at.