### 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 (selected_col == (columns.size() - 1)) {
		if (selected_item->get_first_child() != nullptr && selected_item->is_collapsed()) {
			selected_item->set_collapsed(false);
		} else if (selected_item->get_next_visible()) {
			selected_col = 0;
			_go_down();
		}
	} else {
		if (select_mode == SELECT_MULTI) {
			selected_col++;
			emit_signal(SNAME("cell_selected"));
		} else {
			selected_item->select(selected_col + 1);
		}
	}
	queue_redraw();
	ensure_cursor_is_visible();
	accept_event();
}
void Tree::_go_up() {