Custom color on for class_bg_brush on WindowMainOpts about winsafe HOT 1 CLOSED

This happens because the window demands an owned background brush – the window itself will delete it, see the hbrBackground member of WNDCLASSEX.

In C++, CreateSolidBrush returns a handle with no safety restrictions, and no concept of ownership. WinSafe adds safety restrictions, with CreateSolidBrush returning a guard which will delete the brush automatically. So, Rust won't let you pass this guard to the window, otherwise the brush would be deleted twice.

So, you need to give the brush ownership to the window. Just call leak:

class_bg_brush: gui::Brush::Handle(
	unsafe {
		HBRUSH::CreateSolidBrush(
			winsafe::COLORREF::new(0x0a, 0xba, 0xb5),
		).unwrap().leak()
	},
),

from winsafe.