### Godot version

v4.1.1.stable.official [bd6af8e0e]

### System information

Godot v4.1.1.stable - Ubuntu 22.04.2 LTS 22.04 - Vulkan (Forward+) - integrated Intel(R) UHD Graphics 615 (AML-KBL) () - Intel(R) Core(TM) i3-10100Y CPU @ 1.30GHz (4 Threads)

### Issue description

Summary: When editing the subregion of a StyleBoxTexture, it shows me the entire spritesheet of the Atlas texture, instead of the selected portion of the atlas, making it difficult (and non-intuitive) to correctly select the subregion I need. 

What I expect: I understand that the sub-region may be used to emulate the behavior of a nine-patch. So I would expect to see there the subregion that i selected previously from the Atlas as the texture to be shown.

I have only tested this in a Panel Container

### Steps to reproduce

I found this problem when doing these steps:

- Add a PanelContainer node
- In the inspector select Theme Overrrides -> Style -> new StyleBoxTexture
- In the texture of the StyleBoxTexture select new AtlasTexture
- Dropped the spritesheet in the Atlas of the AtlasTexture
- In Region of the AtlasTexture, selected Edit Region and drew the rectangle on the texture i want:
![image](https://github.com/godotengine/godot/assets/1207326/2e9624b1-63bc-4267-8d7f-59e82df7896e)

- Back in the StyleBoxTexture options, in Sub-Region, clicked on Edit Region to select the nine-patch region i need
- Here is where the region editor shows me the entire spritesheet and not the sub-texture i selected from the atlas. The image below shows the axis correctly positioned for the nine-patch to work, but it is not intuitive because it has to be positioned without seeing the correct texture, making it difficult to finetune for some textures.

![image](https://github.com/godotengine/godot/assets/1207326/a5023afd-7e4b-47c8-adfc-03fda7f6301b)


### Minimal reproduction project

N/A
edit_draw->draw_texture(select_handle, (endpoints[i] + ofs - (select_handle->get_size() / 2)).floor() - draw_ofs * draw_zoom);
		}
		scroll_rect.expand_to(raw_endpoints[i]);
	}
	const Size2 scroll_margin = edit_draw->get_size() / draw_zoom;
	scroll_rect.position -= scroll_margin;
	scroll_rect.size += scroll_margin * 2;
	updating_scroll = true;
	hscroll->set_min(scroll_rect.position.x);
	hscroll->set_max(scroll_rect.position.x + scroll_rect.size.x);
	if (ABS(scroll_rect.position.x - (scroll_rect.position.x + scroll_rect.size.x)) <= scroll_margin.x) {
		hscroll->hide();
	} else {
		hscroll->show();
		hscroll->set_page(scroll_margin.x);
		hscroll->set_value(draw_ofs.x);
	}
	vscroll->set_min(scroll_rect.position.y);
	vscroll->set_max(scroll_rect.position.y + scroll_rect.size.y);
	if (ABS(scroll_rect.position.y - (scroll_rect.position.y + scroll_rect.size.y)) <= scroll_margin.y) {
		vscroll->hide();
		draw_ofs.y = scroll_rect.position.y;
	} else {
		vscroll->show();
		vscroll->set_page(scroll_margin.y);
		vscroll->set_value(draw_ofs.y);
	}
	Size2 hmin = hscroll->get_combined_minimum_size();
	Size2 vmin = vscroll->get_combined_minimum_size();