This happened when I updated to version 0.94 via the git URL in the package manager.

https://github.com/kirurobo/UniWindowController/blame/58de0678d73ca93b42981aa08fd3bcff11659787/UniWinC/Assets/Kirurobo/UniWindowController/Runtime/Scripts/UniWindowMoveHandle.cs#L157

LeftCtrl and RightCtrl to...
|| Input.GetKey(KeyCode.LeftControl) || Input.GetKey(KeyCode.RightControl)

I think it should look like this.