Using Google IME makes the DirectX11 Client window lose focus

Hi, I'm learning Japanese and using Google IME to type in kana.

In the older client, I could switch to hiragana input and start typing just fine, but in the Directx11, the screen loses fullscreen and becomes a window to the side that I have to click again to make fullscreen. It's difficult to type like this! If I play in a window or borderless window, this stops being an issue, but I have lower fps in those modes. How could I fix this and still play in full screen?