### 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
return (selected_item != nullptr);
}
void Tree::clear() {
	ERR_FAIL_COND(blocked > 0);
	if (pressing_for_editor) {
		if (range_drag_enabled) {
			range_drag_enabled = false;
			Input::get_singleton()->set_mouse_mode(Input::MOUSE_MODE_VISIBLE);
			warp_mouse(range_drag_capture_pos);
		}
		pressing_for_editor = false;
	}
	if (root) {
		memdelete(root);
		root = nullptr;
	};
	selected_item = nullptr;
	edited_item = nullptr;
	popup_edited_item = nullptr;
	popup_pressing_edited_item = nullptr;
	queue_redraw();
};
void Tree::set_hide_root(bool p_enabled) {