### 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
int depth = 0;
		TreeItem *next;
		for (TreeItem *item = get_root(); item; item = next) {
			next = item->get_next_visible();
			
			if (next && p_column == 0) {
				if (next->get_parent() == item) {
					depth += 1;
				} else {
					TreeItem *common_parent = item->get_parent();
					while (common_parent != next->get_parent() && common_parent) {
						common_parent = common_parent->get_parent();
						depth -= 1;
					}
				}
			}
			
			Size2 item_size = item->get_minimum_size(p_column);
			if (p_column == 0) {
				item_size.width += theme_cache.item_margin * depth;
			} else {
				item_size.width += theme_cache.h_separation;
			}
			
			min_width = MAX(min_width, item_size.width);
		}
	}
	return min_width;
}
int Tree::get_column_width(int p_column) const {