### 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
for (TreeItem *current = root; current; current = current->get_next_visible()) {
		for (int i = 0; i < columns.size(); i++) {
			if (current->get_text(i) == p_find) {
				return current;
			}
		}
	}
	return nullptr;
}
void Tree::_do_incr_search(const String &p_add) {
	uint64_t time = OS::get_singleton()->get_ticks_usec() / 1000; 
	uint64_t diff = time - last_keypress;
	if (diff > uint64_t(GLOBAL_GET("gui/timers/incremental_search_max_interval_msec"))) {
		incr_search = p_add;
	} else if (incr_search != p_add) {
		incr_search += p_add;
	}
	last_keypress = time;
	int col;
	TreeItem *item = search_item_text(incr_search, &col, true);
	if (!item) {
		return;
	}
	item->select(col);
	ensure_cursor_is_visible();
}
TreeItem *Tree::_find_item_at_pos(TreeItem *p_item, const Point2 &p_pos, int &r_column, int &h, int &section) const {