Hi Experts!:
I am writing to you to see if anyone recognizes this error is appearing in the transaction /MRSS/PLBOORG randomly.
When I want to assign a resource to an operation via drag & drop sometimes the system does not allow the allocation opening a new window in sap indicating that select a valid resource.
The configuration of resources made by the HR module.
As it is an error that appears randomly in the system.
Attached images:
If I assign the resource manually and then I choose to create the operating system assigns
So in short drag & drop functionality does not work. 
Someone will have some tips that can guide me to see if I can fix this....
Regards!
Damy
