Modifying the DOM in an attach or detach listener might cause inconsistent results

When an attach listener makes modifications to the DOM, there can be situations where the attach happens twice (leading to a server-side Can't change id once it has been assigned) or never happens (leading to a client-side Node -1 is already registered). The exact result will vary depending on the relative DOM positions between the node with the attach listener and the newly attached node.

Something similar will most likely also happen detaches, or combinations where an attach listener detaches something or vice versa.

As a workaround, an attach or detach listener can defer the DOM modification using beforeClientResponse.

[johannest]

More information about the issue. It is reproducible also without Spring. Pushed even simplified example into the repository mentioned above.

The root cause is that if you use the same instance of Component such as layout for Grid’s detail row. If you construct a new instance of component used for Grid’s detail row every time, there is no issues.

Steps to reproduce: Navigate to categories, open a details row for a grid row, open another details row for some other grid row, navigate to reviews.

[Juchar]

It seems that the onDetach() is called before the parent member variable is updated, causing the detach listeners to be fired before the node is really detached.

Is this the intended behaviour?