### Godot version

4.0.rc6.mono.official

### System information

macOS 12.0.1

### Issue description

Just a minor visual issue.

When opening an empty directory the focus highlight is drawn incorrectly. It looks like the UI is drawing a smaller rectangle within the main rect:
<img width="1058" alt="Bildschirmfoto 2023-02-28 um 14 13 31" src="https://user-images.githubusercontent.com/11627131/221868794-7450606d-e758-4104-8f33-182d9779d7f8.png">


This behavior also changes when you hover over other items in the view, so I'm not sure if this a general issue with the focus highlighting or just an issue in the directory view:
<img width="1052" alt="Bildschirmfoto 2023-02-28 um 14 32 54" src="https://user-images.githubusercontent.com/11627131/221869308-4756f26e-cda2-4057-be1e-7439030895dc.png">


### Steps to reproduce

1. New Project
2. Browse
3. Create Folder
4. Click or Tab to set focus on the empty directory view

### Minimal reproduction project

N/A
if (state.canvas_instance_data_buffers[state.current_data_buffer_index].last_frame_used < RSG::rasterizer->get_frame_number() - 2) {
#ifndef WEB_ENABLED
				
				glClientWaitSync(state.canvas_instance_data_buffers[state.current_data_buffer_index].fence, 0, 100000000); 
#endif
				state.canvas_instance_data_buffers[state.current_data_buffer_index].last_frame_used = RSG::rasterizer->get_frame_number();
				glDeleteSync(state.canvas_instance_data_buffers[state.current_data_buffer_index].fence);
				state.canvas_instance_data_buffers[state.current_data_buffer_index].fence = GLsync();
			} else {
				
				
				_allocate_instance_data_buffer();
			}
		} else {
			
			state.canvas_instance_data_buffers[state.current_data_buffer_index].last_frame_used = RSG::rasterizer->get_frame_number();
			glDeleteSync(state.canvas_instance_data_buffers[state.current_data_buffer_index].fence);
			state.canvas_instance_data_buffers[state.current_data_buffer_index].fence = GLsync();
		}
	}
	
	uint32_t light_count = 0;
	uint32_t directional_light_count = 0;
	{
		Light *l = p_directional_light_list;
		uint32_t index = 0;
		while (l) {
			if (index == data.max_lights_per_render) {
				l->render_index_cache = -1;