diff --git a/.swcrc b/.swcrc
index b9e4c87..a874d56 100644
--- a/.swcrc
+++ b/.swcrc
@@ -7,6 +7,6 @@
 			"decorators": false,
 			"dynamicImport": false
 		},
-		"target": "esnext"
+		"target": "es2022"
 	}
 }
\ No newline at end of file
diff --git a/static/scripts/components/editor/script.ts b/static/scripts/components/editor/script.ts
index 867992b..169a93f 100644
--- a/static/scripts/components/editor/script.ts
+++ b/static/scripts/components/editor/script.ts
@@ -1,21 +1,77 @@
 import "/static/vendor/ace/ace.js";
 import { $el } from "/static/vendor/domutil/domutil.js";
 
+class EditorTab extends HTMLElement {
+	static observedAttributes = ["name", "selected"];
+
+	private tabEl: HTMLDivElement;
+	private buttonsEl: HTMLDivElement;
+	private root: ShadowRoot;
+
+	constructor() {
+		super();
+		this.root = this.attachShadow({ mode: "open" });
+
+		const style = $el("style");
+		style.textContent = `
+		:host {
+			border: 2px solid var(--table-border-color);
+			padding: 0.5ch 0.8ch;
+			background-color: var(--button-bg);
+			cursor: pointer;
+		}
+		:host([selected="true"]) {
+			background-color: var(--table-border-color);
+			}
+		:host([modified="true"]) .tab-name::after {
+			content: " ᴹ";
+		}
+		:host([unsaved="true"]) {
+			font-style: italic;
+		}
+		`;
+		this.root.append(style);
+
+		this.tabEl = $el("div", { className: "tab-name" }, this.getAttribute("name") || $el("i", "unknown"));
+		this.buttonsEl = $el("div", { className: "buttons" });
+		this.root.append(this.tabEl, this.buttonsEl);
+	}
+
+	connectedCallback() {
+	}
+
+	attributeChangedCallback(name, _, value) {
+		switch (name) {
+			case "name":
+				this.tabEl.textContent = value;
+				break;
+			case "selected":
+				this.classList.toggle("active", Boolean(value));
+				break;
+		}
+	}
+}
+customElements.define("file-editor-tab", EditorTab);
+
+
 class Editor extends HTMLElement {
 	private editor: AceAjax.Editor;
 	private tabEl: HTMLDivElement;
 	private sessions: Record<string, AceAjax.IEditSession>;
 	private root: ShadowRoot;
-	private addTabButton: HTMLDivElement;
+	private addTabButton: EditorTab;
+	private original: Record<string, string>;
 
 	constructor() {
 		super();
 		this.sessions = {};
+		this.original = {};
 		this.root = this.attachShadow({ mode: "open" });
 	}
 
 	connectedCallback() {
-		this.addTabButton = $el("div", { className: "tab" }, "+");
+		this.addTabButton = new EditorTab();
+		this.addTabButton.setAttribute("name", "+");
 		this.addTabButton.addEventListener("click", () => this.#createNewTab());
 		this.tabEl = $el("div", { className: "tab-container" }, this.addTabButton);
 		this.root.append(this.tabEl);
@@ -25,19 +81,10 @@ class Editor extends HTMLElement {
 		.tab-container {
 			display: flex;
 			margin-bottom: -2px;
-
-			& .tab {
-				border: 2px solid var(--table-border-color);
-				padding: 0.5ch 0.8ch;
-				background-color: var(--button-bg);
-				cursor: pointer;
-				&.active {
-					background-color: var(--table-border-color);
-				}
-				&:not(:first-child) {
-					margin-left: -2px;
-				}
-			}
+		}
+		
+		file-editor-tab:not(:first-child) {
+			margin-left: -2px;
 		}
 		`;
 		const slot = $el("slot", { name: "body" });
@@ -65,23 +112,27 @@ class Editor extends HTMLElement {
 	 * @param name File name
 	 * @param content File contents
 	 */
-	addFile(name: string, content: string) {
+	addFile(name: string, content: string, saved = true) {
 		// Add to session list
 		this.sessions[name] = ace.createEditSession(content);
+		this.original[name] = content;
 
 		// TODO replace this with auto-detection
 		this.sessions[name].setMode("ace/mode/nix");
 
 		// Create tab and set as active
-		const tab = this.#addTab(name);
+		const tab = this.#addTab(name, saved);
 		tab.click();
+
+		this.sessions[name].on("change", () => {
+			tab.setAttribute("modified", this.sessions[name].getValue() != this.original[name] ? "true" : "false");
+		});
 	}
 
 	setCurrent(name: string) {
 		this.editor.setSession(this.sessions[name]);
-		this.tabEl.querySelectorAll<HTMLDivElement>(".tab").forEach(el => {
-			if (el.dataset.name === name) el.classList.add("active");
-			else el.classList.remove("active");
+		this.tabEl.querySelectorAll<EditorTab>("file-editor-tab").forEach(el => {
+			el.setAttribute("selected", el.getAttribute("name") == name ? "true" : "false");
 		});
 	}
 
@@ -94,20 +145,18 @@ class Editor extends HTMLElement {
 	 * @param name Tab name
 	 * @returns Tab element
 	 */
-	#addTab(name: string) {
-		const tab = $el("div", {
-			className: "tab",
-			dataset: { name },
-			"@click": () => this.setCurrent(name)
-		}, name);
+	#addTab(name: string, saved = true) {
+		const tab = new EditorTab();
+		tab.setAttribute("name", name);
+		tab.setAttribute("unsaved", saved ? "false" : "true");
+		tab.addEventListener("click", () => this.setCurrent(name));
 		this.tabEl.insertBefore(tab, this.addTabButton);
 		return tab;
 	}
 
 
 	#createNewTab() {
-		this.addFile(`untitled${Object.keys(this.sessions).filter(s => s.startsWith("untitled")).length + 1}`, "");
+		this.addFile(`untitled${Object.keys(this.sessions).filter(s => s.startsWith("untitled")).length + 1}`, "", false);
 	}
 }
-
 customElements.define("file-editor", Editor);
\ No newline at end of file
diff --git a/tsconfig.json b/tsconfig.json
index 4481fed..7ad53dc 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,19 +1,19 @@
 {
 	"compilerOptions": {
-		"target": "esnext",
+		"target": "ES2022",
 		"paths": {
 			"/static/*": [
 				"./static/*"
 			],
 		},
 		"lib": [
-			"ESNext",
+			"ES2022",
 			"DOM"
 		],
 		"rootDir": "./",
 		"baseUrl": "./",
 		"strictNullChecks": true,
-		"declaration": true,
+		"declaration": true
 	},
 	"include": [
 		"./static/**/*.ts",