Programmatically change a color of a subset of a label string

[gaurab21st]

I want to programmatically color each word in a label with different colors. I tried to use selection start and end properties along with text color property. But it was always setting same color to entire text. Am I missing something?

[gaurab21st]

Providing more information:
LabVIEW version: 2013.
I have a test VI where a wire's label color is currently red. I want to change color of it's 4th letter to 6th letter as black.
I tried several code-combination one of them being like the following picture:

Any help will be appriciated.

[gaurab21st]