What are Floating Events?
A floating event is a bit like a task and perhaps most easily explained with an example. Suppose you need to get your hair cut next week. You might put in an appointment on Tuesday, thinking you will likely be able to do it that day. But then you get busy and can't get to it. What you would really like is for that appointment to automatically roll over to the next day if you didn't get to it. A floating appointment does just that. If you created the item as a floating event, it would automatically float from day to day until you marked it as complete. When marked as complete, the appointment is then frozen on that day and does not get advanced any more. A checkmark appears in the circle to indicate that the floating event is complete.
Floating events can be put on any future date, but not a past date. The reason for this is that a floating event that has not been marked as complete must be displayed at the very earliest in today's schedule.
You can set a due date on a floating event - for example, you create a floating event to write a report which you want to start on Tuesday of next week and mark it as having a due date of Friday of that week. When displaying that event, Pimlical shows in brackets at the start of the description how many days out from today it is due (so if it was due in ten days, you would see  at the start of the description field.
Repeat Floating Events
Floating events can also be made to repeat and serve a very useful function for repetitive items that don't have to be completed on a specific day. For example, you might make that haircut appointment a repeat floating event that repeats every two months. That way, every two months, when the repeat floating event's next instance matches today's date, the repeat event itself is rescheduled two months in advance and a non-repeat floating instance is left in today's schedule. There is also an option to reschedule the repeat floating event from the checkoff date. Example, you don't get around to cutting your hair for three weeks, but don't want to be reminded about that haircut in 5 weeks, but rather 8 weeks from when you got your last haircut. By setting that option in the repeat dialog, the repeat floating event will get rescheduled from the date that you actually completed the task.
Advancing of Floating Events
Floating events are advanced automatically by Pimlical at the start of each day, provided that the preference AdvanceFloatingEventsTime is set to a value other than midnight. The actual time set is not relevant - only whether it is set to midnight (which disables this function) or to some other time (which enables it).
If you are using Pimlical on more than one platform, and syncing via any mechanism other than Pimlical's DirectSync, only one of those platforms should advance floating events, as that feature is also used to create new floating reminders as well as non-repeat float instances. If these are created on two separate platforms that end up syncing with each other, such events will end up getting duplicated. It is recommended that you determine which platform is the one that always or is most likely to be turned on first in the day and advance floating events on that platform. This is not an issue with Pimlical's DirectSync as duplicate reminders created on each platform are automatically resolved. However, you should only advance floating events on both platforms if you are exclusively using the local calendar. If you are mixing local calendars and Android calendars it is still recommended that you only advance events on one platform.
Skipping over days
There is an Action tag, FloatDays: which can be used to skip over certain days. The argument for this Action tag is a list of digits which represent days of the week (0=Sunday, 1 = Monday, 2 = Tuesday, etc.) on which this floating event can run. For example, if the floating event is only to appear on weekdays, you would use 12345 as the argument for this tag.
You can use this feature to automatically advance floating events only on the weekend days (example, you want a floating event which only appears on Saturday and Sunday when you are available to work on non-work related items).