Only the first click in a tree works

Only the first click in a JCR tree works. This applies to both the tree of nodes in the Console as the tree of content items in the CMS.

Steps to reproduce in the Console:

1. Login to the Console
2. Click on a tree node to expand it
3. Click on another tree node. It should expand too, but doesn't.

Steps to reproduce in the CMS:

1. Login to the CMS
2. Open the Content perspective
3. Click on a folder to expand it
4. Click on another folder. It should expand too, but doesn't.