Constant Color could be kept when switching for another color attribution mode and

[Einithorynque]

Scenario :

• I set edges' color as Constant Color
• I chose my constant color : red rather than gray
• I try setting the nodes' color from degree
• I switch back to Constant Color

What it does :

The constant color is now gray (default constant color)

Expected :

I would have like red staying the constant color