Design time preview caching

There is some sort of preview caching going on when you design filters. For example if you click on a Blur and wait for it to complete the first time, then later on when you select it, it shows instantly.

It is a very useful feature that gives a more responsive interface. However it can also be quite annoying when you try compare branches and in general figure out how expensive the different parts are in your filter (regarding rendering time).

While it might help you design filters faster, it is definitely not helping you design faster filters

I suggest an option in the preview popup menu where you can disable preview caching.