My test PBB was open as I tried a Build for some changes. The book's tab was closed but I got this message:
"Could not remove existing resource. Please close all other open panels and try again."
I had to restart Logos4 to get it to build successfully.
1616.Logos4_PBB-Remove.zip
NB. Closing all open panels did not make sense if it was the resource file that could not be removed.