Consider renaming GladePropertyClass to GladePropertyDef and GladeSignalClass to GladeSignalDef
Having GladePropertyClass/GladeSignalClass being its own thing and not related to GladeProperty/GladeSignal makes Vala unable to use libgladeui, It probably causes issues with the whole GObject Introspection system.
Renaming them from Glade*Class
to Glade*Def
is probably alright as it would stand for definition.
Edited by Corentin Noël