- load Pic3D
- open "Property list" view
- uncheck the "use color" property
--> the 2D render windows go black, the image planes in 3D show the correct content for the 2D windows
Explanation: the "use color" property is supposed to determine whether rendering should use the image's "color" property to generate a "black to chosen-color"-LUT. If the property is disabled, a built-in default-rainbow LUT is used.
Although this is not a perfect solution (having general LUT support for 2D-rendering would be better), it should work consistently