Double-clicking behaviour (to add / update items) does not match documentation

[TheophileMot]

In general, the clicking behaviour in vis-timeline seems inconsistent. The docs say that new items are added by double-clicking an empty space, and that items are updated by double-clicking them. However, depending on the options and where you click within the boundary, double-clicking an item often creates a new one.

As a reproduction, double-click near the edge of any item in this official example. This will incorrectly create a new item.

[tengl]

We have an addition to this.

We have editable and read-only items (editable: false) in the timeline. When double clicking on an item, we open a form for editing or viewing if read-only. This used to work when using the components from vis ("vis": "^4.21.0-EOL").

After upgrade to "vis-data": "7.1.6" and "vis-timeline": "^7.7.2", double click behavior has changed. Items that are read-only does not receive the double click event, or rather, the onAdd event gets triggered before, which opens our form with a new item instead of the existing item.

Using onUpdate does not work on read-only items. The behavior can be observed in the examples
https://visjs.github.io/vis-timeline/examples/timeline/editing/editingItemsCallbacks.html
and
https://visjs.github.io/vis-timeline/examples/timeline/interaction/eventListeners.html

Just set one item to editable:false and test. One interesting thing is that if you click at a specific pace (not too fast, not too slow), onAdd does not trigger but doubleclick does.

Is this a bug or a feature? Should onAdd be triggered when clicking on a read-only item? I would say a bug and no, but I guess it could be useful for some.

[tengl]

By the way, a work-around that works in our case it to enable editing on all items and then check if we should be able to edit in onMove and onMoving, and abort edit if not. Not a nice work-around as the pointer indicates that the item is editable, but it works.