In an browser subapp configured to use a jsonDatasource, and with a defaultAction configured to launch the detail subapp, double-clicking on an item causes an exception.

However if the item is first selected (so that it is hilighted), and then you doubleclick on it, then it performs the action correctly.

Example app which exhibits this problem:

https://git.magnolia-cms.com/users/czimmermann/repos/restclient-testing/browse/light-modules/rc-transportation-demo/apps/stations.yaml

To reproduce, just download/clone the full project and drop it into your light-modules/resources directory.

Note: Im not sure if the problem is specifically related to the jsonDatasource, but I was not able to reproduce in any other M6 ui apps. 

(Note2: Its possible that the app is incorrectly configured! I just added the defaultAction property. Is something else required?)