### Godot version

v4.0.beta.custom_build [eaf306e0b]

### System information

Windows 10

### Issue description

Selecting a `Window` node in the Editor's SceneTree results in the message
```
editor/editor_data.cpp:1058 - Parameter "p_node" is null.
```
and the Inspector shows empty content instead of the Window's properties.

I would expect, that clicking on a node in the SceneTree lets me edit the properties of the node.

Bisecting shows that this behavior got introduced in #71770

### Steps to reproduce

1. Create a Window node
2. Click on the Window node in the Editor's SceneTree

### Minimal reproduction project

N/A
child_container->add_child(rotation_offset);
		label = memnew(Label);
		label->set_text(TTR("Rotation Step:"));
		child_container->add_child(label);
		label->set_h_size_flags(Control::SIZE_EXPAND_FILL);
		rotation_step = memnew(SpinBox);
		rotation_step->set_min(-SPIN_BOX_ROTATION_RANGE);
		rotation_step->set_max(SPIN_BOX_ROTATION_RANGE);
		rotation_step->set_suffix("deg");
		rotation_step->set_h_size_flags(Control::SIZE_EXPAND_FILL);
		rotation_step->set_select_all_on_focus(true);
		child_container->add_child(rotation_step);
		container->add_child(memnew(HSeparator));
		child_container = memnew(GridContainer);
		child_container->set_columns(2);
		container->add_child(child_container);
		label = memnew(Label);
		label->set_text(TTR("Scale Step:"));
		child_container->add_child(label);
		label->set_h_size_flags(Control::SIZE_EXPAND_FILL);
		scale_step = memnew(SpinBox);
		scale_step->set_min(SPIN_BOX_SCALE_MIN);
		scale_step->set_max(SPIN_BOX_SCALE_MAX);
		scale_step->set_allow_greater(true);
		scale_step->set_h_size_flags(Control::SIZE_EXPAND_FILL);
		scale_step->set_step(0.01f);
		scale_step->set_select_all_on_focus(true);
		child_container->add_child(scale_step);
	}
	void set_fields(const Point2 p_grid_offset, const Point2 p_grid_step, const int p_primary_grid_steps, const real_t p_rotation_offset, const real_t p_rotation_step, const real_t p_scale_step) {