### 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
ERR_FAIL_INDEX_V(p_column, cells.size(), false);
	return cells[p_column].checked;
}
bool TreeItem::is_indeterminate(int p_column) const {
	ERR_FAIL_INDEX_V(p_column, cells.size(), false);
	return cells[p_column].indeterminate;
}
void TreeItem::propagate_check(int p_column, bool p_emit_signal) {
	bool ch = cells[p_column].checked;
	if (p_emit_signal) {
		tree->emit_signal(SNAME("check_propagated_to_item"), this, p_column);
	}
	_propagate_check_through_children(p_column, ch, p_emit_signal);
	_propagate_check_through_parents(p_column, p_emit_signal);
}
void TreeItem::_propagate_check_through_children(int p_column, bool p_checked, bool p_emit_signal) {
	TreeItem *current = get_first_child();
	while (current) {
		current->set_checked(p_column, p_checked);
		if (p_emit_signal) {
			current->tree->emit_signal(SNAME("check_propagated_to_item"), current, p_column);
		}
		current->_propagate_check_through_children(p_column, p_checked, p_emit_signal);
		current = current->get_next();
	}
}
void TreeItem::_propagate_check_through_parents(int p_column, bool p_emit_signal) {