Fixes #29610: Improve presentation of problem matcher picker

src/vs/workbench/parts/tasks/browser/buildQuickOpen.ts

@@ -29,7 +29,9 @@ class TaskEntry extends base.TaskEntry {
 		let task = this._task;
 		if (this.taskService.canCustomize() && task.problemMatchers === void 0 || task.problemMatchers.length === 0) {
 			this.attachProblemMatcher(task).then((task) => {
-				this.doRun(task);
+				if (task) {
+					this.doRun(task);
+				}
 			});
 			return true;
 		} else {

src/vs/workbench/parts/tasks/browser/quickOpen.ts

@@ -23,6 +23,7 @@ import { ActionBarContributor, ContributableActionProvider } from 'vs/workbench/
 
 interface ProblemMatcherPickEntry extends IPickOpenEntry {
 	matcher: NamedProblemMatcher;
+	learnMore?: boolean;
 }
 
 export class TaskEntry extends Model.QuickOpenEntry {
@@ -50,20 +51,36 @@ export class TaskEntry extends Model.QuickOpenEntry {
 			if (matcher.name === matcher.label) {
 				entries.push({ label: matcher.name, matcher: matcher });
 			} else {
-				entries.push({ label: nls.localize('entries', '{0} [${1}]', matcher.label, matcher.name), matcher: matcher });
+				entries.push({
+					label: matcher.label,
+					description: `$${matcher.name}`,
+					matcher: matcher
+				});
 			}
 		}
 		if (entries.length > 0) {
-			entries.push({ label: 'Continue without scanning the build output', separator: { border: true }, matcher: undefined });
+			entries = entries.sort((a, b) => a.label.localeCompare(b.label));
+			entries[0].separator = { border: true };
+			entries.unshift(
+				{ label: nls.localize('continueWithout', 'Continue without scanning the build output'), matcher: undefined },
+				{ label: nls.localize('learnMoreAbout', 'Learn more about scanning the build output'), matcher: undefined, learnMore: true }
+			);
 			return this.quickOpenService.pick(entries, {
 				placeHolder: nls.localize('selectProblemMatcher', 'Select for which kind of errors and warnings to scan the build output')
 			}).then((selected) => {
-				if (selected && selected.matcher) {
-					let newTask = Objects.deepClone(task);
-					let matcherReference = `$${selected.matcher.name}`;
-					newTask.problemMatchers = [matcherReference];
-					this.taskService.customize(task, { problemMatcher: [matcherReference] }, true);
-					return newTask;
+				if (selected) {
+					if (selected.learnMore) {
+						this.taskService.openDocumentation();
+						return undefined;
+					} else if (selected.matcher) {
+						let newTask = Objects.deepClone(task);
+						let matcherReference = `$${selected.matcher.name}`;
+						newTask.problemMatchers = [matcherReference];
+						this.taskService.customize(task, { problemMatcher: [matcherReference] }, true);
+						return newTask;
+					} else {
+						return task;
+					}
 				} else {
 					return task;
 				}

src/vs/workbench/parts/tasks/browser/taskQuickOpen.ts

@@ -28,7 +28,11 @@ class TaskEntry extends base.TaskEntry {
 		}
 		let task = this._task;
 		if (this.taskService.canCustomize() && task.group === TaskGroup.Build && ((task.problemMatchers === void 0) || task.problemMatchers.length === 0)) {
-			this.attachProblemMatcher(task).then(task => this.doRun(task));
+			this.attachProblemMatcher(task).then(task => {
+				if (task) {
+					this.doRun(task);
+				}
+			});
 			return true;
 		} else {
 			return this.doRun(task);

src/vs/workbench/parts/tasks/common/taskService.ts

@@ -30,6 +30,7 @@ export interface ITaskProvider {
 export interface ITaskService extends IEventEmitter {
 	_serviceBrand: any;
 	configureAction(): Action;
+	openDocumentation(): void;
 	build(): TPromise<ITaskSummary>;
 	rebuild(): TPromise<ITaskSummary>;
 	clean(): TPromise<ITaskSummary>;

src/vs/workbench/parts/tasks/electron-browser/task.contribution.ts

@@ -14,6 +14,7 @@ import * as nls from 'vs/nls';
 import { TPromise } from 'vs/base/common/winjs.base';
 import Severity from 'vs/base/common/severity';
 import * as Objects from 'vs/base/common/objects';
+import URI from 'vs/base/common/uri';
 import { IStringDictionary } from 'vs/base/common/collections';
 import { Action } from 'vs/base/common/actions';
 import * as Dom from 'vs/base/browser/dom';
@@ -45,6 +46,7 @@ import { ServicesAccessor } from 'vs/platform/instantiation/common/instantiation
 import { ProblemMatcherRegistry } from 'vs/platform/markers/common/problemMatcher';
 import { IStorageService, StorageScope } from 'vs/platform/storage/common/storage';
 import { IProgressService2, IProgressOptions, ProgressLocation } from 'vs/platform/progress/common/progress';
+import { IOpenerService } from 'vs/platform/opener/common/opener';
 
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { IModelService } from 'vs/editor/common/services/modelService';
@@ -573,7 +575,8 @@ class TaskService extends EventEmitter implements ITaskService {
 		@ITerminalService private terminalService: ITerminalService,
 		@IWorkbenchEditorService private workbenchEditorService: IWorkbenchEditorService,
 		@IStorageService private storageService: IStorageService,
-		@IProgressService2 private progressService: IProgressService2
+		@IProgressService2 private progressService: IProgressService2,
+		@IOpenerService private openerService: IOpenerService
 	) {
 
 		super();
@@ -742,6 +745,10 @@ class TaskService extends EventEmitter implements ITaskService {
 		this.storageService.store(TaskService.RecentlyUsedTasks_Key, JSON.stringify(values), StorageScope.WORKSPACE);
 	}
 
+	public openDocumentation(): void {
+		this.openerService.open(URI.parse('https://go.microsoft.com/fwlink/?LinkId=733558'));
+	}
+
 	public build(): TPromise<ITaskSummary> {
 		return this.getTaskSets().then((values) => {
 			let runnable = this.createRunnableTask(values, TaskGroup.Build);