Identifies which paper a paper-targeting hook should resolve: a registered
paper id, a React ref to a paper, or a dia.Paper instance directly. These
hooks never throw — an unresolved target falls back to the current Paper
context or the default paper.
Identifies which paper a paper-targeting hook should resolve: a registered paper id, a React ref to a paper, or a
dia.Paperinstance directly. These hooks never throw — an unresolved target falls back to the current Paper context or the default paper.