### 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;
					}
				}
				if (!root || (!root->get_first_child() && hide_root)) {
					break;
				}
				click_handled = false;
				pressing_for_editor = false;
				propagate_mouse_activated = false;
				int x_limit = get_size().width - theme_cache.panel_style->get_minimum_size().width;
				if (v_scroll->is_visible()) {
					x_limit -= v_scroll->get_minimum_size().width;
				}
				cache.rtl = is_layout_rtl();
				blocked++;
				propagate_mouse_event(pos + theme_cache.offset, 0, 0, x_limit + theme_cache.offset.width, mb->is_double_click(), root, mb->get_button_index(), mb);
				blocked--;
				if (pressing_for_editor) {
					pressing_pos = mb->get_position();
					if (rtl) {
						pressing_pos.x = get_size().width - pressing_pos.x;
					}
				}
				if (mb->get_button_index() == MouseButton::RIGHT) {
					break;
				}
				if (drag_touching) {
					set_physics_process_internal(false);
					drag_touching_deaccel = false;
					drag_touching = false;