diff --git a/arduino-ide-extension/src/browser/arduino-ide-frontend-module.ts b/arduino-ide-extension/src/browser/arduino-ide-frontend-module.ts
index f131b1e2..b4eb99b9 100644
--- a/arduino-ide-extension/src/browser/arduino-ide-frontend-module.ts
+++ b/arduino-ide-extension/src/browser/arduino-ide-frontend-module.ts
@@ -33,7 +33,9 @@ import {
     ApplicationShell as TheiaApplicationShell,
     ShellLayoutRestorer as TheiaShellLayoutRestorer,
     CommonFrontendContribution as TheiaCommonFrontendContribution,
-    KeybindingRegistry as TheiaKeybindingRegistry
+    KeybindingRegistry as TheiaKeybindingRegistry,
+    TabBarRendererFactory,
+    ContextMenuRenderer
 } from '@theia/core/lib/browser';
 import { MenuContribution } from '@theia/core/lib/common/menu';
 import { ApplicationShell } from './theia/core/application-shell';
@@ -120,6 +122,8 @@ import { OutputServicePath, OutputService } from '../common/protocol/output-serv
 import { NotificationCenter } from './notification-center';
 import { NotificationServicePath, NotificationServiceServer } from '../common/protocol';
 import { About } from './contributions/about';
+import { IconThemeService } from '@theia/core/lib/browser/icon-theme-service';
+import { TabBarRenderer } from './theia/core/tab-bars';
 
 const ElementQueries = require('css-element-queries/src/ElementQueries');
 
@@ -329,4 +333,12 @@ export default new ContainerModule((bind, unbind, isBound, rebind) => {
 
     bind(NotificationCenter).toSelf().inSingletonScope();
     bind(NotificationServiceServer).toDynamicValue(context => WebSocketConnectionProvider.createProxy(context.container, NotificationServicePath)).inSingletonScope();
+
+    // Enable the dirty indicator on uncloseable widgets.
+    rebind(TabBarRendererFactory).toFactory(context => () => {
+        const contextMenuRenderer = context.container.get<ContextMenuRenderer>(ContextMenuRenderer);
+        const decoratorService = context.container.get<TabBarDecoratorService>(TabBarDecoratorService);
+        const iconThemeService = context.container.get<IconThemeService>(IconThemeService);
+        return new TabBarRenderer(contextMenuRenderer, decoratorService, iconThemeService);
+    });
 });
diff --git a/arduino-ide-extension/src/browser/style/editor.css b/arduino-ide-extension/src/browser/style/editor.css
new file mode 100644
index 00000000..220c7bd3
--- /dev/null
+++ b/arduino-ide-extension/src/browser/style/editor.css
@@ -0,0 +1,6 @@
+/* Show the dirty indicator on unclosable widgets. On hover, it should still show the dot instead of the X. */
+/* https://github.com/arduino/arduino-pro-ide/issues/380 */
+.p-TabBar.theia-app-centers .p-TabBar-tab.p-mod-closable.theia-mod-dirty > .p-TabBar-tabCloseIcon:hover {
+    background-size: 13px;
+    background-image: var(--theia-icon-circle);
+}
diff --git a/arduino-ide-extension/src/browser/style/index.css b/arduino-ide-extension/src/browser/style/index.css
index bb8c88c3..68e984f9 100644
--- a/arduino-ide-extension/src/browser/style/index.css
+++ b/arduino-ide-extension/src/browser/style/index.css
@@ -5,6 +5,7 @@
 @import './arduino-select.css';
 @import './status-bar.css';
 @import './terminal.css';
+@import './editor.css';
 
 .theia-input.warning:focus {
     outline-width: 1px;
diff --git a/arduino-ide-extension/src/browser/theia/core/tab-bars.ts b/arduino-ide-extension/src/browser/theia/core/tab-bars.ts
new file mode 100644
index 00000000..c6d547b2
--- /dev/null
+++ b/arduino-ide-extension/src/browser/theia/core/tab-bars.ts
@@ -0,0 +1,15 @@
+import { TabBar } from '@phosphor/widgets';
+import { Saveable } from '@theia/core/lib/browser/saveable';
+import { TabBarRenderer as TheiaTabBarRenderer } from '@theia/core/lib/browser/shell/tab-bars';
+
+export class TabBarRenderer extends TheiaTabBarRenderer {
+
+    createTabClass(data: TabBar.IRenderData<any>): string {
+        let className = super.createTabClass(data);
+        if (!data.title.closable && Saveable.isDirty(data.title.owner)) {
+            className += ' p-mod-closable';
+        }
+        return className;
+    }
+
+}