I've reported this a couple of times over the months (years?) that this feature has been in MC17. I can't figure out why it hasn't been solved as it should be an incredibly simple fix.
When creating ringtones, the preview starts automatically even when you are just deciding where in the file you want the thing to begin. So if I start typing 93.0 the ringtone will start previewing from 9 seconds in if I'm not quick with my typing. Besides being incredibly annoying, it also makes the whole thing feel clunky. Furthermore, a full 30 second (or however long) preview does not play. It's just the first few seconds. Perhaps that is intended, but it doesn't really seem like that would be the desired function.
It would be nice if we could specify how long we wanted the ringtone to go from any time from 0.0 to 30.0 seconds. This should also be an incredibly easy fix. It would also be nice if we could save these directly as a .m4r file instead of having to do the conversion in iTunes.