Because WebDAV takes a while to re-serialize the calendar, sequentially dragging and dropping multiple events in a WebDAV calendar can trigger a confusing situation fairly frequently: * drag one event to a different time * try to start dragging a second event * because computer is busy serializing the change from the first drag, no obvious UI feedback happens * let go of the mouse button * wait for a moment until the serializing finishes * out of nowhere, a drag box appears!
The bugspam monkeys have struck again. They are currently chewing on default assignees for Calendar. Be afraid for your sanity!
I can't reproduce this issue using Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:22.214.171.124pre) Gecko/20080220 Calendar/0.8pre. Dan, do you still see this issue using a recent 0.8pre nightly build?