### 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
}
			if (i == 0) {
				if (p_item->cells[0].selected && select_mode == SELECT_ROW) {
					Rect2i row_rect = Rect2i(Point2i(theme_cache.panel_style->get_margin(SIDE_LEFT), item_rect.position.y), Size2i(get_size().width - theme_cache.panel_style->get_minimum_size().width, item_rect.size.y));
					
					
					if (rtl) {
						row_rect.position.x = get_size().width - row_rect.position.x - row_rect.size.x;
					}
					if (has_focus()) {
						theme_cache.selected_focus->draw(ci, row_rect);
					} else {
						theme_cache.selected->draw(ci, row_rect);
					}
				}
			}
			if ((select_mode == SELECT_ROW && selected_item == p_item) || p_item->cells[i].selected || !p_item->has_meta("__focus_rect")) {
				Rect2i r = cell_rect;
				p_item->set_meta("__focus_rect", Rect2(r.position, r.size));
				if (select_mode != SELECT_ROW) {
					if (rtl) {
						r.position.x = get_size().width - r.position.x - r.size.x;
					}
					if (p_item->cells[i].selected) {
						if (has_focus()) {
							theme_cache.selected_focus->draw(ci, r);
						} else {
							theme_cache.selected->draw(ci, r);
						}
					}