SDL window creates desktop artifacts

I’m using a KDE desktop with two monitors, and recently moved to SDL2 from glfw. One artifact I’ve noticed with SDL when a new window is created, is that the taskbar at the bottom of the screen changes color (it goes grey for the duration of the SDL window), and the other monitor flickers (once on creation of the window, and once again on closing the window).

Does anyone know what might be causing this? I’m using NVIDIA 390.87 drivers.