Application Version
4.0.0
Platform
Arch Linux
Printer
N/A
Actual Results
Select Preview > Color Scheme > Line type.
Two colours in particular are difficult to tell apart: Top / Bottom is yellow, and Infill is orange.
Expected results
It should be easy to tell them apart. There are quite a few unused colours, so using more distinct colours would be helpful. Alternatively, the colours could be customisable.
Additional Information
I've picked a simple area for the screenshot, but with more complex models, it can be difficult to discern infill from top/bottom.

I agree with this actually. Bit of a long-standing issue that has always been a bit of a papercut.
Similarly with support and support interface.

Better.
That looks great; thank you!