A slight bug to report.
When entering the times of an event, set the start time, then set the end time, then use the slider to keep increasing the end time hour until it gets to 23. One more movement and it goes "up" to "00", taking the start hour back to 00 with it!
If this is meant to be midnight the next day, the end date isn't incremented. If this is meant to be a wrap-around, it should go back to the earliest start time which is on or after the end time, not zero (i.e. take minutes into account when deciding the hour).
Personally, I'd prefer it go to the next day. I found this while trying to set and event from 18:30 to midnight, and I hate having to make do with "23:55" or whatever.
Indeed, why not have the slider increment a field and be able to affect all those of longer lengths when changing a value, i.e. if you really wanted, you could use it to scoot through years of times just by using the minute field. An extreme case, but you see what I mean?