0f1ccdd167
In Geometry Nodes workspace, the viewport has a default value of 0.0 for `gpencil_vertex_paint_opacity`, this causes material preview to not show proper vertex color even when strokes have color. Considering this property is a bit obscure, setting a default value of 1.0 here makes sense and it's also consistent with the rest of the viewport editors in other workspaces. Pull Request: https://projects.blender.org/blender/blender/pulls/139356