First of all after 4 hours of debugging I have no problem with my code. But I'm curious why I had issue that I had.
I created fullscreen window with d3d11 rendering. Problem occurred when I tried to alt-tab window and didn't have Present() in my loop (I simply found this issue before implementing rendering function). In that case after minimizing window Red and Blue channels on my screen were swapped (yes, literally).
It took me long time to find because I suspected my swap chain or window itself (sdl). Can you help me find the reason of this bug- for educational purposes?