Anyone have a gauge on why sometimes titles slow projects down to a crawl?
I've noticed it over the past year or two but haven't been able to pinpoint a solution. Now I'm editing reels in a film (30 min each) and I'm finding myself waiting 3-5 minutes for the spinning wheel while I try to change the text in normal titles. Specifically they are subtitles that are using the title tool. Nothing fancy, just text.
In general that should not happen. Obviously editors use titles frequently and it normally works OK.
The spinning wait disk or "beachball" does not indicate the app is simply busy. Rather it indicates the app's UI thread is not responding to user commands or UI events. App developers are supposed to avoid making blocking API calls on the UI thread, rather spin those off to another thread. Then when that call is finished it should notify the main thread which can update the UI.
I think the previous design of the FCP plugin framework, FxPlug 3.x, would often cause that. The updated FxPlug 4 framework (mandatory on Apple Silicon) should provide smoother, more consistent UI response from compute-intensive threads in 3rd-party plugins.
Anytime you adjust a title, generator, or adjustment layer, all clips in all layers below that spanned range must be recomputed. If any of those clips contain compute-intensive Fx it could take a while, but normally it should not cause a protracted beachball.
Your problem regards editing responsiveness but there can also be an issue during export. FCP titles are produced by Motion and in some cases the Motion runtime apparently prevents render cache from being used to expedite export encoding -- even if there are no render dots showing and the timeline appears fully rendered. This can manifest as very slow export behavior if compute-intensive Fx (e.g. Neat Video) are used. In that cases timeline response is good if the timeline is fully rendered but export performance is slow because the timeline must be recomputed.
In general I'd recommend evaluating all 3rd-party Fx, and upgrading any which are old. You can also try resetting FCP preferences (item 11 on this list): support.apple.com/en-us/HT203477
If you are using an external monitor or wireless audio, as a troubleshooting step try disconnecting/disabling those and see if the problem gets any better.
There was an older problem with the Chrome browser which would cause various FCP hang-type problems. I don't know if that has been fixed on new versions of Chrome.