Unable to set libPaths for TERR Tools to use via GUI

When I try to install a package via the TERR tools package manager it gives an error saying I don't have permission to write to the folder:

I found that I can use this in the console to add another location that I have write access to:

.libPaths(c("c:\\Users\\me\\TERR", .libPaths()))

However, this isn't saved and when I try and load libraries that are installed in this location Spotfire can't find it.

How do I get Spotfire to use this location permanently from the UI?