I have Elements 12. I can not use the "zoom burst effect". I the programe I can ad zoom burst and the picture gets blured as it should. But the moment I try to sharpen part og´f the picture the whole picture imidiatly gets sharp. What is wrong?

I have Elements 12. I can not use the "zoom burst effect". In the programe I can ad zoom burst and the picture gets blured as it should. But the moment I try to sharpen part of the picture the whole picture imidiatly gets sharp. What is wrong?