Steps to reproduce :

1. If the JcrViewTool is opened, close it and restart your app.
2. At this point, "Ametys.repository.RepositoryApp.getCurrentWorkspace()" would normally return null. (which is the reason of the bug).
3. Open the AmetysViewTool, select a node and click on the "Open JCR node" action button

This is due to the combobox of the JcrViewTool which was never initialized and thus Ametys.repository.RepositoryApp.currentWorkspace is still _null