### 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)

spin->set_read_only(p_read_only);
}
void EditorPropertyEasing::_drag_easing(const Ref<InputEvent> &p_ev) {
	if (is_read_only()) {
		return;
	}
	const Ref<InputEventMouseButton> mb = p_ev;
	if (mb.is_valid()) {
		if (mb->is_double_click() && mb->get_button_index() == MouseButton::LEFT) {
			_setup_spin();
		}
		if (mb->is_pressed() && mb->get_button_index() == MouseButton::RIGHT) {
			preset->set_position(easing_draw->get_screen_position() + mb->get_position());
			preset->reset_size();
			preset->popup();
			
			dragging = false;
			easing_draw->queue_redraw();
		}
		if (mb->get_button_index() == MouseButton::LEFT) {
			dragging = mb->is_pressed();
			
			easing_draw->queue_redraw();
		}
	}
	const Ref<InputEventMouseMotion> mm = p_ev;
	if (dragging && mm.is_valid() && (mm->get_button_mask().has_flag(MouseButtonMask::LEFT))) {