This is a partial revert of c9ef1ed2. I don't know where I got the
idea that CMP does not support _SAT, but I suspect that my driver at the time was broken.

comctl32/treeview: TVM_EXPAND with TVE_TOGGLE action shouldn't always notify as it does on user input.

Outputs not written by the pixel shader are undefined in GL, but in D3D the
render target is unmodified.