Thanks for the report! We’ve tracked an issue internally to look at this for our upcoming CI 9 release. Certainly interesting how the background goes white!
There are a couple other things that might be of interest to you — we fixed support for HiDPI composite icons, like those you might see in the Project Explorer to look good at 200% and we just finished moderating about 250 icon submissions from users, a handful of which were in CDT.
And in short, certainly not intended! Hopefully we can get to the bottom of it.