### 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
} break;
			case TreeItem::CELL_MODE_RANGE: {
				if (!c.text.is_empty()) {
					
					popup_menu->clear();
					for (int i = 0; i < c.text.get_slice_count(","); i++) {
						String s = c.text.get_slicec(',', i);
						popup_menu->add_item(s.get_slicec(':', 0), s.get_slicec(':', 1).is_empty() ? i : s.get_slicec(':', 1).to_int());
					}
					popup_menu->set_size(Size2(col_width, 0));
					popup_menu->set_position(get_screen_position() + Point2i(col_ofs, _get_title_button_height() + y_ofs + item_h) - theme_cache.offset);
					popup_menu->popup();
					popup_edited_item = p_item;
					popup_edited_item_col = col;
					
					bring_up_editor = false;
				} else {
					if (x >= (col_width - item_h / 2)) {
						
						bool up = p_pos.y < (item_h / 2);
						if (p_button == MouseButton::LEFT) {
							if (range_click_timer->get_time_left() == 0) {
								range_item_last = p_item;
								range_up_last = up;
								range_click_timer->set_wait_time(0.6);
								range_click_timer->set_one_shot(true);
								range_click_timer->start();
							} else if (up != range_up_last) {
								return -1; 
							}