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The create-node list is now a two-level tree: a header per node source (USD, MaterialX, Arnold, Cycles - from the Sdr sourceType, with glslfx and OSL merged into USD so core nodes don't appear twice) containing Hypershade-style category sub-trees (Material / Texture / Geometry / Utility / Light) derived from Sdr context, terminal output types, role, and name keywords. Duplicate collapsing is per (source, label) so same-named nodes from different providers both stay; searching forces all sections open. The TAB popup shows [Source/Category] per entry. The browser and preview columns get drag splitters (viewport-divider styling, clamped widths); the canvas absorbs the remainder. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>