I'm having trouble replicating the WPF data exchange example in the manual found here:

Manual/WPF element/Guidelines for developers/Data exchange between zenon and WPF user controls/Data exchange using dependency properties

Namely, in the dialog for adding WPF links the variable "ValueA" doesn't appear in the "Action link" properties list for the WPF element "AdditionalControl".

Manual example:

Could anyone confirm that this example works? I've tired to follow the instructions and copy/pasted the code, and have tried a number of times from scratch to no avail.

What are the prerequisites for the property "ValueA" to appear? I may be blind to the wording in the manual so if someone could describe this in other words, it may be useful.