### 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 (select_mode == SELECT_MULTI) {
		if (!next) {
			return;
		}
		selected_item = next;
		emit_signal(SNAME("cell_selected"));
		queue_redraw();
	} else {
		int col = selected_col < 0 ? 0 : selected_col;
		while (next && !next->cells[col].selectable) {
			next = next->get_next_visible();
		}
		if (!next) {
			return; 
		}
		next->select(col);
	}
	ensure_cursor_is_visible();
	accept_event();
}
bool Tree::_scroll(bool p_horizontal, float p_pages) {
	ScrollBar *scroll = p_horizontal ? (ScrollBar *)h_scroll : (ScrollBar *)v_scroll;
	double prev_value = scroll->get_value();
	scroll->set_value(scroll->get_value() + scroll->get_page() * p_pages);
	return scroll->get_value() != prev_value;
}
void Tree::gui_input(const Ref<InputEvent> &p_event) {