### Godot version

4.0 beta 10

### System information

Windows 11 Vulkan

### Issue description

Looked through the issues list, but couldn't find something like this, sorry in advance if this has already been reported.

There is a few cases (in the pictures below) where list of Actions in Input Map may not always show a scrollbar even if the actions list overflows (I imagine this could also happen for the widget that Input Map uses).

![image](https://user-images.githubusercontent.com/39958198/210003566-cf60dbaf-921f-485b-b0a9-51ffc28d0244.png)

![New Bitmap image](https://user-images.githubusercontent.com/39958198/210004079-8eb2e6a1-0cf5-4a7c-8905-a4e3cfd0ec5d.png)

![image](https://user-images.githubusercontent.com/39958198/210004165-a6b6790b-248a-4f68-b4d0-b44b25afdf4f.png)

![image](https://user-images.githubusercontent.com/39958198/210004537-aca52194-a464-48b9-b818-24782706de45.png)


### Steps to reproduce

The pictures are clearer than anything I could write here: "a picture is worth 1000 words"

### Minimal reproduction project

N/A
}
			Point2 mouse_position = get_viewport()->get_mouse_position() - get_global_position();
			if (scrolling && get_rect().grow(theme_cache.scroll_border).has_point(mouse_position)) {
				Point2 point;
				if ((ABS(mouse_position.x) < ABS(mouse_position.x - get_size().width)) && (ABS(mouse_position.x) < theme_cache.scroll_border)) {
					point.x = mouse_position.x - theme_cache.scroll_border;
				} else if (ABS(mouse_position.x - get_size().width) < theme_cache.scroll_border) {
					point.x = mouse_position.x - (get_size().width - theme_cache.scroll_border);
				}
				if ((ABS(mouse_position.y) < ABS(mouse_position.y - get_size().height)) && (ABS(mouse_position.y) < theme_cache.scroll_border)) {
					point.y = mouse_position.y - theme_cache.scroll_border;
				} else if (ABS(mouse_position.y - get_size().height) < theme_cache.scroll_border) {
					point.y = mouse_position.y - (get_size().height - theme_cache.scroll_border);
				}
				point *= theme_cache.scroll_speed * get_physics_process_delta_time();
				point += get_scroll();
				h_scroll->set_value(point.x);
				v_scroll->set_value(point.y);
			}
		} break;
		case NOTIFICATION_DRAW: {
			v_scroll->set_custom_step(theme_cache.font->get_height(theme_cache.font_size));
			update_scrollbars();
			RID ci = get_canvas_item();
			Ref<StyleBox> bg = theme_cache.panel_style;
			Point2 draw_ofs;
			draw_ofs += bg->get_offset();
			Size2 draw_size = get_size() - bg->get_minimum_size();
			if (v_scroll->is_visible()) {
				draw_size.width -= v_scroll->get_minimum_size().width;