### 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
c.selected = false;
				}
			}
		} else if (select_mode == SELECT_SINGLE || select_mode == SELECT_MULTI) {
			if (!r_in_range && &selected_cell == &c) {
				if (!selected_cell.selected || allow_reselect) {
					selected_cell.selected = true;
					selected_item = p_selected;
					selected_col = i;
					emit_signal(SNAME("cell_selected"));
					if (select_mode == SELECT_MULTI) {
						emit_signal(SNAME("multi_selected"), p_current, i, true);
					} else if (select_mode == SELECT_SINGLE) {
						emit_signal(SNAME("item_selected"));
					}
				} else if (select_mode == SELECT_MULTI && (selected_item != p_selected || selected_col != i)) {
					selected_item = p_selected;
					selected_col = i;
					emit_signal(SNAME("cell_selected"));
				}
			} else {
				if (r_in_range && *r_in_range && !p_force_deselect) {
					if (!c.selected && c.selectable) {
						c.selected = true;
						emit_signal(SNAME("multi_selected"), p_current, i, true);
					}
				} else if (!r_in_range || p_force_deselect) {
					if (select_mode == SELECT_MULTI && c.selected) {
						emit_signal(SNAME("multi_selected"), p_current, i, false);
					}