### Godot version

4.0.beta12

### System information

Windows 11, RTX 3080

### Issue description

When a Window Node is created with it's Transparent flag set to true and Project Settings --> Display --> Window --> Subwindows --> Embed Subwindows is false, the Window has a black background. By cycling the transparent flag from false and back to true again, during runtime, the window's background then becomes transparent. 

### Steps to reproduce

Attempt to create a Non-embedded Subwindow with a transparent background using the appropriate flags. 

### Minimal reproduction project

Note: this project is from Reddit user [gongpha](https://www.reddit.com/user/gongpha/) and his Reddit post [Learning a Godot 4.0 Window node](https://www.reddit.com/r/godot/comments/xr8yxn/learning_a_godot_40_window_node/)

https://github.com/gongpha/godot4-window-test
Key modifiers = p_keycode & KeyModifierMask::MODIFIER_MASK;
	Key keycode_no_mod = (Key)(p_keycode & KeyModifierMask::CODE_MASK);
	if (keycode_no_mod == Key::PRINT ||
			keycode_no_mod == Key::KP_ADD ||
			keycode_no_mod == Key::KP_5 ||
			(keycode_no_mod >= Key::KEY_0 && keycode_no_mod <= Key::KEY_9)) {
		return p_keycode;
	}
	unsigned int scancode = KeyMappingWindows::get_scancode(keycode_no_mod);
	if (scancode == 0) {
		return p_keycode;
	}
	HKL current_layout = GetKeyboardLayout(0);
	UINT vk = MapVirtualKeyEx(scancode, MAPVK_VSC_TO_VK, current_layout);
	if (vk == 0) {
		return p_keycode;
	}
	UINT char_code = MapVirtualKeyEx(vk, MAPVK_VK_TO_CHAR, current_layout) & 0x7FFF;
	
	
	if (char_code >= 32 && char_code <= 127) {
		
		if (char_code == (unsigned int)Key::BRACKETLEFT || char_code == (unsigned int)Key::BRACKETRIGHT) {
			char_code += 32;
		}
		return (Key)(char_code | (unsigned int)modifiers);
	}
	return (Key)(KeyMappingWindows::get_keysym(vk) | modifiers);
}
String _get_full_layout_name_from_registry(HKL p_layout) {