Floating time events incorrectly interpreted as UTC
In GNOME Calendar, "floating time" events are incorrectly interpreted as UTC.
Calendar wrongly "converts" that to local time for display, and "from" local time when writing.
For example, on a system with a Europe/London time zone (currently UTC+1), the following:
DTSTART:20170818T140000
DTEND:20170818T150000
is displayed in Calendar as 15:00-16:00 (i.e. interpreted as 14:00-15:00 UTC, then displayed as 15:00-16:00 UTC+1).
Instead, it should be interpreted as 14:00-15:00 in the user's current time zone.
Editing the event time continues this misinterpretation - the start/end are written out in floating time format, as if it is a UTC time being written. So editing the above example in Calendar and changing the times to 16:00-17:00 results in:
DTSTART:20170818T150000
DTEND:20170818T160000
The iCalendar DATE-TIME value type forms are specified here: https://tools.ietf.org/html/rfc5545#section-3.3.5
Link to original bug (#786155)
Note: this affects both .ics file imports and webcal / online calendars.