### Godot version

4.0-rc6

### System information

Fedora 37, Mesa Intel ADL GT2

### Issue description

Code that works as expected at runtime fails with Nil references to (assigned) exported vars in the editor:

![tool_global_position_error](https://user-images.githubusercontent.com/364501/222031460-ffb1ecbd-5175-4a42-8470-25285ba5f821.png)


### Steps to reproduce

Try to access the `global_position` of a `Node3D` that's assigned to an exported var.

See that it works at runtime.

See that it errors in the editor with:

> Invalid get index 'global_position' (on base: 'Nil').

### Minimal reproduction project

[tool_test.zip](https://github.com/godotengine/godot/files/10856640/tool_test.zip)

int layer_count = grid->layer_count;
	layers->clear();
	for (int i = 0; i < layer_count; i++) {
		const String name = get_layer_name(i);
		if (name.is_empty()) {
			continue;
		}
		layers->add_check_item(name, i);
		int idx = layers->get_item_index(i);
		layers->set_item_checked(idx, grid->value & (1 << i));
	}
	if (layers->get_item_count() == 0) {
		layers->add_item(TTR("No Named Layers"));
		layers->set_item_disabled(0, true);
	}
	layers->add_separator();
	layers->add_icon_item(get_theme_icon("Edit", "EditorIcons"), TTR("Edit Layer Names"), grid->layer_count);
	Rect2 gp = button->get_screen_rect();
	layers->reset_size();
	Vector2 popup_pos = gp.position - Vector2(layers->get_contents_minimum_size().x, 0);
	layers->set_position(popup_pos);
	layers->popup();
}
void EditorPropertyLayers::_menu_pressed(int p_menu) {