Recent versions of FE fixed the incompatibility with InfiniBoard, and both can be used together. FE no longer allows InfiniBoard to create hidden rows in folders, which was the earlier problem with it. While writing this I just found that FE is now compatible with 4.1 and have reinstalled it over InfiniBoard with no problem. (I had uninstalled it prior to upgrading to 4.1 because for a while it was not compatible.)