Console - Unable to click view mixin types by clicking the small triangle

1. Login to CMS console using valid user-id in FF3.6
2. Navigate any node where mixin or types or properties is not expanded
3. Click on the small triangle besides (one of the above)

Expected - The page should expand to show the hidden elements
Actual - Nothing happens

This was a new feature introduced in Hippo Firday and works fine in archetype
https://issues.onehippo.com/browse/CMS7-5402
Occurs only in FF3.6