After installing Feature Pack 30015 in CQ5.3, some folders that should be expandable in the Site Admin or DAM Admin tree panel are no longer expandable.
A limitation was added to the Site Admin and DAM Admin as part of Feature Pack 30015. The default limitation is 30. This means if a folder has more than 30 sub-nodes, it will not be expandable.
You can increase the limit to 500 by doing the following:
Alternatively you can create an overlay in the /apps section as well. The steps almost remain the same.