The Sims Team@tigerlillysim This is a known issue with the (now default on most systems) DirectX 11 version of Sims 4. I've therefore merged your post with the DX11 feedback thread.
Your options are to play in windowed mode, or perhaps windowed fullscreen if it works for you—I've seen mixed reports—or to rever to DirectX 9 mode, which is a check box on the graphics options page, to the right of post processing.
@tigerlillysim I'm sure it'll be fixed eventually, but I have no idea when. It was actually a problem before, and fixed (from what I heard), so it shouldn't be too much trouble to fix again. Hopefully.
