Aux window: improve MRU order of editor groups (fix microsoft#199529)

Author: bpasero

src/vs/workbench/browser/parts/editor/editorParts.ts

@@ -6,7 +6,7 @@
 import { localize } from 'vs/nls';
 import { EditorGroupLayout, GroupDirection, GroupLocation, GroupOrientation, GroupsArrangement, GroupsOrder, IAuxiliaryEditorPart, IAuxiliaryEditorPartCreateEvent, IEditorDropTargetDelegate, IEditorGroupsService, IEditorSideGroup, IFindGroupScope, IMergeGroupOptions } from 'vs/workbench/services/editor/common/editorGroupsService';
 import { Emitter } from 'vs/base/common/event';
-import { DisposableStore, IDisposable } from 'vs/base/common/lifecycle';
+import { DisposableStore, IDisposable, toDisposable } from 'vs/base/common/lifecycle';
 import { GroupIdentifier } from 'vs/workbench/common/editor';
 import { EditorPart, MainEditorPart } from 'vs/workbench/browser/parts/editor/editorPart';
 import { IEditorGroupView, IEditorPartsView } from 'vs/workbench/browser/parts/editor/editor';
@@ -23,6 +23,8 @@ export class EditorParts extends MultiWindowParts<EditorPart> implements IEditor
 
 	readonly mainPart = this._register(this.createMainEditorPart());
 
+	private readonly mostRecentActiveParts = [this.mainPart];
+
 	constructor(
 		@IInstantiationService private readonly instantiationService: IInstantiationService
 	) {
@@ -82,10 +84,13 @@ export class EditorParts extends MultiWindowParts<EditorPart> implements IEditor
 
 	private registerEditorPartListeners(part: EditorPart, disposables: DisposableStore): void {
 		disposables.add(part.onDidFocus(() => {
+			this.doUpdateMostRecentActive(part, true);
+
 			if (this._parts.size > 1) {
 				this._onDidActiveGroupChange.fire(this.activeGroup); // this can only happen when we have more than 1 editor part
 			}
 		}));
+		disposables.add(toDisposable(() => this.doUpdateMostRecentActive(part)));
 
 		disposables.add(part.onDidChangeActiveGroup(group => this._onDidActiveGroupChange.fire(group)));
 		disposables.add(part.onDidAddGroup(group => this._onDidAddGroup.fire(group)));
@@ -98,6 +103,20 @@ export class EditorParts extends MultiWindowParts<EditorPart> implements IEditor
 		disposables.add(part.onDidChangeGroupLocked(group => this._onDidChangeGroupLocked.fire(group)));
 	}
 
+	private doUpdateMostRecentActive(part: EditorPart, makeMostRecentlyActive?: boolean): void {
+		const index = this.mostRecentActiveParts.indexOf(part);
+
+		// Remove from MRU list
+		if (index !== -1) {
+			this.mostRecentActiveParts.splice(index, 1);
+		}
+
+		// Add to front as needed
+		if (makeMostRecentlyActive) {
+			this.mostRecentActiveParts.unshift(part);
+		}
+	}
+
 	private getGroupsLabel(index: number): string {
 		return localize('groupLabel', "Window {0}", index + 1);
 	}
@@ -186,10 +205,14 @@ export class EditorParts extends MultiWindowParts<EditorPart> implements IEditor
 	getGroups(order = GroupsOrder.CREATION_TIME): IEditorGroupView[] {
 		if (this._parts.size > 1) {
 			let parts: EditorPart[];
-			if (order === GroupsOrder.MOST_RECENTLY_ACTIVE) {
-				parts = distinct([this.activePart, ...this._parts]); // put active part first in this order
-			} else {
-				parts = this.parts;
+			switch (order) {
+				case GroupsOrder.GRID_APPEARANCE: // we currently do not have a way to compute by appearance over multiple windows
+				case GroupsOrder.CREATION_TIME:
+					parts = this.parts;
+					break;
+				case GroupsOrder.MOST_RECENTLY_ACTIVE:
+					parts = distinct([...this.mostRecentActiveParts, ...this.parts]); // always ensure all parts are included
+					break;
 			}
 
 			return parts.map(part => part.getGroups(order)).flat();