diff --git a/src/app/editor.ts b/src/app/editor.ts
index 73cba68..7b0850c 100644
--- a/src/app/editor.ts
+++ b/src/app/editor.ts
@@ -1,9 +1,4 @@
-import {
-    Transaction,
-    StateEffect,
-    Compartment,
-    Extension,
-} from "@codemirror/state";
+import { Transaction, Compartment, Extension } from "@codemirror/state";
 import {
     EditorView,
     keymap,
@@ -27,8 +22,10 @@ import {
 } from "@codemirror/language";
 import { languages } from "@codemirror/language-data";
 import { highlightSelectionMatches, searchKeymap } from "@codemirror/search";
+import van from "vanjs-core";
 
 import { OpenFile } from "./filestate";
+import { Displayable } from "./editorgrid";
 
 const fixedHeightEditor = EditorView.theme({
     "&": {
@@ -44,12 +41,13 @@ const fixedHeightEditor = EditorView.theme({
     ".cm-scroller": { overflow: "auto scroll" },
 });
 
-export class Editor {
+export class Editor implements Displayable {
     view: EditorView;
     file: OpenFile;
     deleteFn?: () => void;
 
     private wordWrapCompartment = new Compartment();
+    private languageCompartment = new Compartment();
 
     dispatch(tr: Transaction, inhibitSync = false) {
         this.view.update([tr]);
@@ -95,6 +93,7 @@ export class Editor {
                 fixedHeightEditor,
                 kmap,
                 this.wordWrapCompartment.of(EditorView.lineWrapping),
+                this.languageCompartment.of([]),
                 lineNumbers(),
                 highlightSpecialChars(),
                 foldGutter(),
@@ -113,12 +112,16 @@ export class Editor {
                 // lintKeymap,
             ],
         });
-        LanguageDescription.matchFilename(languages, file.filePath.val)
-            ?.load()
-            .then((Lang) => {
-                const eff = StateEffect.appendConfig.of(Lang);
-                this.view.dispatch({ effects: [eff] });
-            });
+
+        van.derive(() => {
+            LanguageDescription.matchFilename(languages, file.filePath.val)
+                ?.load()
+                .then((Lang) => {
+                    // const eff = StateEffect.appendConfig.of(Lang);
+                    const eff = this.languageCompartment.reconfigure(Lang);
+                    this.view.dispatch({ effects: [eff] });
+                });
+        });
     }
 
     get dom() {
@@ -130,9 +133,13 @@ export class Editor {
         this.view.focus();
     }
 
+    title(): string {
+        return this.file.filePath.val + (this.file.isDirty() ? "*" : "");
+    }
+
     changeWidth(increment: number) {
         const w = parseInt(window.getComputedStyle(this.view.dom).width, 10);
-        this.view.dom.style.width = (w + increment) + 'px';
+        this.view.dom.style.width = w + increment + "px";
         return true;
     }
 
diff --git a/src/app/editorgrid.ts b/src/app/editorgrid.ts
index 5743fa5..70e37d9 100644
--- a/src/app/editorgrid.ts
+++ b/src/app/editorgrid.ts
@@ -6,7 +6,18 @@ import { OpenFile } from "./filestate";
 import * as u from "./utils";
 import { Editor } from "./editor";
 
-const EditorWrapper = (editor: State<Editor>, del: () => void, k: number) => {
+export interface Displayable {
+    setDeleteFunction(del: () => void): void;
+    title(): string;
+    close(): void;
+    dom: HTMLElement;
+}
+
+const EditorWrapper = (
+    editor: State<Displayable>,
+    del: () => void,
+    k: number,
+) => {
     // Set the delete function on the editor when it's created
     van.derive(() => {
         if (editor.val) {
@@ -18,12 +29,7 @@ const EditorWrapper = (editor: State<Editor>, del: () => void, k: number) => {
         { class: "flex flex-col" },
         v.div(
             { class: "flex" },
-            v.span(
-                { class: "mx-1 flex-1" },
-                () =>
-                    editor.val.file.filePath.val +
-                    (editor.val.file.isDirty() ? "*" : ""),
-            ),
+            v.span({ class: "mx-1 flex-1" }, () => editor.val.title()),
             u.InlineButton(() => editor.val.close(), "Close", "❌"),
         ),
         v.div({ class: "flex-auto h-4" }, editor.val.dom),
@@ -55,6 +61,7 @@ const TabHeader = (tab: State<Editor[]>, del: () => void, k: number) =>
         v.span({ class: "mx-1 flex-1" }, "Tab " + k),
         u.InlineButton(del, "Close", "❌"),
     );
+
 const EditorGrid = (tab: State<Editor[]>, del: () => void, k: number) => {
     console.log("Rendering", tab.val, "with key", k);
     const main = v.main({
@@ -64,12 +71,15 @@ const EditorGrid = (tab: State<Editor[]>, del: () => void, k: number) => {
     vanX.list(main, tab.val, EditorWrapper);
     return main;
 };
+
 const TabBar = v.div({ class: "flex-none flex" });
+
 export const EditorTabs = v.div(
     {
         class: "flex flex-col flex-auto min-w-4",
     },
     TabBar,
 );
+
 vanX.list(TabBar, editors, TabHeader);
 vanX.list(EditorTabs, editors, EditorGrid);
diff --git a/src/app/filestate.ts b/src/app/filestate.ts
index 8be28ef..9100815 100644
--- a/src/app/filestate.ts
+++ b/src/app/filestate.ts
@@ -40,13 +40,14 @@ export class OpenFile {
     }
 
     private setPath(path: string) {
-        delete openFiles[this.filePath?.val];
+        delete openFiles[this.filePath.val];
         this.filePath.val = path;
         openFiles[path] = this;
+        // TODO: what if openFiles[path] already exists?
     }
 
     async saveFile() {
-        if (this.filePath) {
+        if (this.filePath.val) {
             await window.electronAPI.saveFile(
                 this.rootState.val.doc.toString(),
                 this.filePath.val,