instead of <hide>true</hide>. This is consistent with other places in fgfs, like menu entries, hud elements, subsystem switches, etc.
SGPropertyNode to guarded ones. This is also done for JSBSim/JSBSim.hxx, for which JSB had given explicit permission a while ago. I postponed that back then, but now is the time.
DOCS/README.layout in the base package for details, along with the modified dialog files.