gradientdiffusemethod causes disappearing material when initially assigned, until texture is set

[rob-bateman]

Steps to reproduce

• open blank lib, create sphere geometry, create mesh
• create new material on the mesh, create new lightpicker on material, create new directional light of lightpicker
• in shading sub-panel of material, select gradientdiffusemethod from diffuse dropdown

Expected result

Gradient diffuse method is applied to the mesh with the default texture

actual result

Gradient diffuse method casues mateiral to disappear

further investigation

going into the gradient diffuse method properties and selecting a different texture causes the material to reappear. Re-selecting the default texture causes the material to disappear again, suggesting the problem is with the default texture not being correctly applied to the gradientdiffusemethod

[keyemkey]

Material disappears only iа diffuse texture and gradient texture are the same