dev: restore last active viewlet to speed up dev flow

src/vs/workbench/browser/parts/sidebar/sidebarPart.ts

@@ -44,6 +44,8 @@ import {KeyMod, KeyCode} from 'vs/base/common/keyCodes';
 
 export class SidebarPart extends Part implements IViewletService {
 
+	public static activeViewletSettingsKey = 'workbench.sidebar.activeviewletid';
+
 	public serviceId = IViewletService;
 
 	private instantiationService: IInstantiationService;
@@ -234,6 +236,9 @@ export class SidebarPart extends Part implements IViewletService {
 		// Remember Viewlet
 		this.activeViewlet = viewlet;
 
+		// Store in preferences
+		this.storageService.store(SidebarPart.activeViewletSettingsKey, this.activeViewlet.getId(), StorageScope.WORKSPACE);
+
 		// Remember
 		this.lastActiveViewletId = this.activeViewlet.getId();
 

src/vs/workbench/browser/workbench.ts

@@ -199,9 +199,14 @@ export class Workbench implements IPartService {
 
 			// Show default viewlet unless sidebar is hidden or we dont have a default viewlet
 			let registry = (<IViewletRegistry>Registry.as(ViewletExtensions.Viewlets));
-			if (!this.sideBarHidden && !!registry.getDefaultViewletId()) {
-				let viewletTimerEvent = timer.start(timer.Topic.STARTUP, strings.format('Opening Viewlet: {0}', registry.getDefaultViewletId()));
-				viewletAndEditorPromises.push(this.sidebarPart.openViewlet(registry.getDefaultViewletId(), false).then(() => viewletTimerEvent.stop()));
+			let viewletId = registry.getDefaultViewletId();
+			if (!this.workbenchParams.configuration.env.isBuilt) {
+				viewletId = this.storageService.get(SidebarPart.activeViewletSettingsKey, StorageScope.WORKSPACE, registry.getDefaultViewletId()); // help developers and restore last view
+			}
+
+			if (!this.sideBarHidden && !!viewletId) {
+				let viewletTimerEvent = timer.start(timer.Topic.STARTUP, strings.format('Opening Viewlet: {0}', viewletId));
+				viewletAndEditorPromises.push(this.sidebarPart.openViewlet(viewletId, false).then(() => viewletTimerEvent.stop()));
 			}
 
 			// Check for configured options to open files on startup and resolve if any or open untitled for empty workbench