I'm following this old houdini tutorial from cmiVFX, to shatter geo David Gary, makes a VOP SOP first to displace the grid points then he makes a VOP SOP to color the primitives, everything looks great and works, BUT, he modifies the frequency of the voronoise in the VOPs, and it updates LIVE on the viewport, which is NOT happening here, I have to save the VOP to get the results.
check the image, using houdini apprentice 9.5 here maybe there's a setting or something
Don't change it in VOPs. Make a Parameter VOP that wires into that. Now change it from SOPs instead. When you're changing it in VOPs, it needs to recompile the shader.