
After trying to move a task using the mouse in the Gannt chart the mouse stuck to the task and would not release. After logging out and back in the task start date went to the year 6509 and would not change even when edited with the edit popup. The popup would allow changing it, but the task refused to accept and move to the new date. A screen capture can be seen here.
I tried restarting the browser, clearing the cache, and finally deleted the task. The problematic task was actually a sub-task, and when I deleted it (sub-task) it also took out the parent task and the other siblings too.