When trying out the different fx, there are some that take a lot more processing than others. While this is happening, the user can’t really tell that Optics is “thinking”.
For example, it takes a full 5 seconds for the screen to change when I select s_lightleak, among others.
At the least, the system wait cursor should be used to indicate that Optics is doing something in response to a user click on an effect
Lenovo Yoga 720
Core i7-7700 2.8Ghz quad core, 8 logical