diff --git a/src/vs/code/electron-main/menus.ts b/src/vs/code/electron-main/menus.ts
index ede6bf9306ad5294d72aa0e645b9fb51d8672028..9725c2a12191cca5d12fa1ea50b0c3b0713f3c36 100644
--- a/src/vs/code/electron-main/menus.ts
+++ b/src/vs/code/electron-main/menus.ts
@@ -660,7 +660,12 @@ export class VSCodeMenu {
 	private toggleDevTools(): void {
 		const w = this.windowsService.getFocusedWindow();
 		if (w && w.win) {
-			w.win.webContents.toggleDevTools();
+			const contents = w.win.webContents;
+			if (w.hasHiddenTitleBarStyle() && !w.win.isFullScreen() && !contents.isDevToolsOpened()) {
+				contents.openDevTools({ mode: 'undocked' }); // due to https://github.com/electron/electron/issues/3647
+			} else {
+				contents.toggleDevTools();
+			}
 		}
 	}
 
diff --git a/src/vs/code/electron-main/window.ts b/src/vs/code/electron-main/window.ts
index 14a6082dd4351d9c26aa36a61cdb7138619c7e96..98b9fc294c3e2ec7ee7bc03af70d9135cc3185ac 100644
--- a/src/vs/code/electron-main/window.ts
+++ b/src/vs/code/electron-main/window.ts
@@ -227,6 +227,10 @@ export class VSCodeWindow {
 		this.registerListeners();
 	}
 
+	public hasHiddenTitleBarStyle(): boolean {
+		return this.options && this.options.titleBarStyle === 'custom';
+	}
+
 	public get isPluginDevelopmentHost(): boolean {
 		return !!this._extensionDevelopmentPath;
 	}
diff --git a/src/vs/platform/windows/electron-main/windowsService.ts b/src/vs/platform/windows/electron-main/windowsService.ts
index a45b968ae9830d482409e878185fe09b41296d32..4b36cfab711c2c66f4fd99a9da1e5bb18e04e188 100644
--- a/src/vs/platform/windows/electron-main/windowsService.ts
+++ b/src/vs/platform/windows/electron-main/windowsService.ts
@@ -61,7 +61,12 @@ export class WindowsService implements IWindowsService {
 		const vscodeWindow = this.windowsMainService.getWindowById(windowId);
 
 		if (vscodeWindow) {
-			vscodeWindow.win.webContents.toggleDevTools();
+			const contents = vscodeWindow.win.webContents;
+			if (vscodeWindow.hasHiddenTitleBarStyle() && !vscodeWindow.win.isFullScreen() && !contents.isDevToolsOpened()) {
+				contents.openDevTools({ mode: 'undocked' }); // due to https://github.com/electron/electron/issues/3647
+			} else {
+				contents.toggleDevTools();
+			}
 		}
 
 		return TPromise.as(null);