grouped timeline-item initially not displayed after setGroups

[aschiffmann]

When creating a new empty timeline and calling setGroups() afterwards, it happens in some cases that an item is not visible initially, only when scrolling the timeline to the right or zooming out.
Here is a jsfiddle with an simple example of the Bug: http://jsfiddle.net/n08dLsbw/

Apparently for the bug to happen, there are at least two items needed in a group, one which starts right of the current display-range and on which starts left end ends right of the current range.

However this bug is very critical, since you can never trust the timeline that really all existing items are actually visible.
Is there a way to prevent this behaviour?

[aschiffmann]

Unfortunately I was not able to find the reason for the Bug in the Code, I only noticed the following:

• the bug doesn't occur when I comment the code of the function ItemSet._onRemoveGroups(ids) , so the bug seems to be that groups are falsely removed or not readded
• the bug must have been introduces with version 6.0.0 because in 5.1.0 I cannot reproduce it

[Poulpy]

To add to the last answer, commenting the call to the dispose() method inside the method onRemoveGroups, did the trick for me !