Bad contrast for the scrollbar with the black theme

Hello,

I am using Qt Creator with the black theme, and the contrast of the bar to handle the scrollbar is very poor. It is especially problematic when I have a lot of notification in the scrollbar area (from clang code model per example), then I just do not see any more where is the bar (see screenshot).

Can it be possible to increase the contrast there with the black theme ?

Thank you !