Description of problem:
For some reason, this particular resource throws an error when removing it from a group.  It appears it can be added just fine, but trying to drag it back over to the resource list gives an error

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.  Create a mixed group of various sundry resources, "MixMix". 
2.  Inventory > Groups > Mixed Group > "MixMix"
3.  Click on Inventory > Membership subtab of the group view
4.  Begin dragging various other resources over to the right-hand pane.   Assure "Bundle Handler - Ant" is one of them.
5.  Attempt to drag resources back.  Again, assure "Bundle Handler - Ant" is one of them.  View results

Actual results:
The resource in question seem to be readily addable, but attempting to remove it nets an error message:

Failure in Datasource [ADD]  Hovering atop the error icon nets a "java.lang.UnsupportedOperationException" error

Expected results:


Additional info: