### 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 (mb->get_button_index() == MouseButton::LEFT) {
				if (single_select_defer) {
					select_single_item(single_select_defer, root, single_select_defer_column);
					single_select_defer = nullptr;
				}
				range_click_timer->stop();
				if (pressing_for_editor) {
					if (range_drag_enabled) {
						range_drag_enabled = false;
						Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_VISIBLE);
						warp_mouse(range_drag_capture_pos);
					} else {
						Rect2 rect = get_selected()->get_meta("__focus_rect");
						Point2 mpos = mb->get_position();
						int icon_size_x = 0;
						Ref<Texture2D> icon = get_selected()->get_icon(selected_col);
						if (icon.is_valid()) {
							Rect2i icon_region = get_selected()->get_icon_region(selected_col);
							if (icon_region == Rect2i()) {
								icon_size_x = icon->get_width();
							} else {
								icon_size_x = icon_region.size.width;
							}
						}
						
						if (rtl) {
							mpos.x = get_size().width - (mpos.x + icon_size_x);
						} else {
							mpos.x -= icon_size_x;
						}