Help! UV Editor - Dark Blue Shells and cant display texture tiles.

[Anonymous]

I opened a scene file today to start sorting out my UV tiles for export, I can't figure out why the shells which I previously laid out have turned dark blue, are snapping to the grid (no free manipulation) and the texture tile won't display. I haven't changed anything since the last time I opened the file yesterday and I have no idea why this is happening. 

[damaggio]

just read the Documentation, it’s all in there.