All open applications placed on main display after sleep

Solution 1:

Stay works on Lion. You may be experiencing an upgrade issue. From their FAQ:

Why won’t Stay restore my windows since I upgraded to Lion?

A number of the interface changes in Lion have affected Stay’s ability to match windows stored on Snow Leopard to windows on Lion. If you’re experiencing difficulty with a small number of windows, the simplest solution is to use Stay’s window linking feature to manually link the troublesome windows to their stored counterparts.

If you’re having trouble with a large number of windows you may find it easier to recreate your stored windows on Lion.