From Xojo Documentation
| This item was deprecated in version 2019r2.
Supported PlatformsProject Types: Desktop Platforms: Windows
Indicates whether the entire Canvas is erased when doing any drawing operations or resizing.
It defaults to True for backwards compatibility.
This property is only used on Windows. Its setting has no effect on macOS or Linux.
This code in the Open event handler of a Canvas enables double-buffering and disables EraseBackground: