Models / Scalar Display: Display defined color for areas below threshold

Dear Slicer developers,

may I make a feature request? In the models module, scalars can by displayed on the surface using a custom color palette. Also, there is a threshold function which allows the display only of those parts of the model surface with associated scalar values within the thresholds.
Would it be possible to add an option to this threshold function to not hide the out-of-threshold areas, but display them in a certain color?
In my use case, there is scalar data for each surface vertex. Valid data is usually in the 0.0 to +20.0 range and should be displayed using the rainbow color scale with a range of 0.5 (red) to 1.5 (pink). However, there are vertices where the input data was actuallly invalid, those are encoded as the value -10000 and it would be great if those areas would be displayed gray (independently of the actual range for the valid scalars).
In Slicer <= 4.11.0 I found the workaround to create 2 copies of the model, with the one higher up in the subject hierarchy list being all gray and the second one having the colors and a lower threshold of -9000. Thus, all the -1000 values are invisible and the gray “background model” shines through.

However, starting with v 4.13 and above, there are some flickering artifacts where the background shines through in colored areas.

It would be therefore really helpful if I could retire this workaround with the second copy and simply define a color for areas outside the threshold.
(Simply appending the color scale with 0 = gray does not really work, since I need values between 0 and the lower limit of the range to be red and only those with the exact vallue -1000 to be grey.)

I hope that makes sense?

Thank you and best regards

You can achieve this by modifying the color table. See these examples:

You can remove the flicker by making the model slightly transparent (0.99 may suffice) and enable depth peeling in the 3D view controller.

Prof. Lasso, thank you for your quick reply.
Probably the creation of a custom color table might be the best thing to do.
The slightly transparent models do not really look the way it should (although the artifacts disappear, there is a surprising amount of background color being mixed into the foreground (color-table defined) color even with .99 transparency.
Thank you