UG reads DGF file on all ranks

For one of our project we wanted to switch from ALUGrid to UGGrid. We are using a DGF file with parameters. Unfortunately, For UGGrid the DGF file is read on all ranks and using loadbalance on the GridPtr causes a segementation fault as the parameters are on all ranks.

Reading the file on all ranks in contrast to the current documentation of the DGFParser which says only rank 0 will read the file. Therefore this seems a bug in UG. I will try to fix it myself.

On the other hand, I noticed when diving into the ALUGrid code that there must be some magic setting in the DGF file that allows ALUGrid to read a distributed grid. I guess this is specific to ALUGrid, right? Is this documented somewhere?

Reported here because the code for UGGrid is in dune-grid.