- Sometimes it takes effect fairly fast, sometimes very slowly - usually slowly (although the preview in the navigator is usually redrawn more quickly).
- Sometimes in Develop Module, the main view is redrawn, sometimes it isn't - usually it isn't (although the preview in the navigator is usually redrawn).
The changes generally show up in the history list fairly fast. And if they appear to not have taken effect (e.g. sliders haven't changed or main view not redrawn), I can "always" click somewhere else in the history list, then back to the top and the changes will kick in.