### 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
if (!selected_from_canvas) {
		_reset_drag();
	}
	selected_from_canvas = false;
}
void CanvasItemEditor::edit(CanvasItem *p_canvas_item) {
	Array selection = editor_selection->get_selected_nodes();
	if (selection.size() != 1 || Object::cast_to<Node>(selection[0]) != p_canvas_item) {
		_reset_drag();
		// Clear the selection
		editor_selection->clear(); //_clear_canvas_items();
		editor_selection->add_node(p_canvas_item);
	}
}
void CanvasItemEditor::_update_scrollbars() {