@JJMGSOFTWORKS I completely forgot about this! Sorry. I probably have some time to check this out tomorrow.
@JJMGSOFTWORKS Your technique only compiles the pixel shader. The ViewportSize variable is only used in the vertex shader. Because the vertex shader is not compiled the ViewportSize variable isn’t used and is optimized out by the effect compiler. You should also compile the vertex shader in the technique to get this to work.