### 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
TreeItem *loop = this;
	TreeItem *next_item = this->_get_next_visible(p_wrap);
	while (next_item && !next_item->is_visible()) {
		next_item = next_item->_get_next_visible(p_wrap);
		if (next_item == loop) {
			
			next_item = nullptr;
			break;
		}
	}
	return next_item;
}
TreeItem *TreeItem::get_child(int p_idx) {
	_create_children_cache();
	if (p_idx < 0) {
		p_idx += children_cache.size();
	}
	ERR_FAIL_INDEX_V(p_idx, children_cache.size(), nullptr);
	return children_cache.get(p_idx);
}
int TreeItem::get_visible_child_count() {