well, that was an easy fix

src/lib/editor.tsx

@@ -38,12 +38,14 @@ export default function Editor({
 		state().markdown.textAt(0).node.textContent = ev.key;
 	}
 
-	useEffect(() =>
+	useEffect(() => {
 		document.addEventListener(
 			"selectionchange",
 			(ev) => state().focused && onSelectionChange(ev)
-		)
-	);
+		);
+
+		state().markdown.node = ref.current;
+	}, []);
 
 	const onFocusChange = (focused: boolean) => {
 		state().focused = focused;

src/lib/markdown.tsx

@@ -150,7 +150,7 @@ export class Paragraph extends NodeCollection<Node> {
 export class Markdown extends NodeCollection<Paragraph> {
 	public lookup: Map<globalThis.Node, Node> = new Map();
 
-	public constructor(element: HTMLDivElement) {
+	public constructor() {
 		super(0);
 		this.NodeCreated.on((node) => {
 			console.log("created node:", node);