If you change your theme, it will also change the window background color to what is set or saved for the selected theme.ĮXAMPLE: Window background color when changed to 'yellow' The window background color you set will only be applied to your current theme. This tutorial will show you how to change the window background color used for your account in Windows 10. The window background color is white by default in Windows 10. The window color is the background color used in classic Win32 system windows, dialogs, and property pages in Windows 10. How to Change Window Background Color in Windows 10