fix(ui): guarantee orchestrator thread/chat pane restores after subtask completion

src/core/task/Task.ts

@@ -1623,6 +1623,11 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 		this.isPaused = false
 		this.childTaskId = undefined
 
+		const provider = this.providerRef.deref()
+		if (provider) {
+			await provider.handleModeSwitch(this.pausedModeSlug)
+		}
+
 		this.emit(RooCodeEventName.TaskUnpaused, this.taskId)
 
 		// Fake an answer from the subtask that it has completed running and

src/core/task/__tests__/Task.subtask-mode-restore.spec.ts

@@ -0,0 +1,71 @@
+import { describe, it, expect, vi, beforeEach } from "vitest"
+import { Task } from "../Task"
+import { ClineProvider } from "../../webview/ClineProvider"
+import { TodoItem } from "@roo-code/types"
+
+describe("Task subtask mode restoration", () => {
+	let parentTask: Task
+	let mockProvider: any
+
+	beforeEach(() => {
+		mockProvider = {
+			handleModeSwitch: vi.fn().mockResolvedValue(undefined),
+			log: vi.fn(),
+			deref: vi.fn().mockReturnValue({
+				handleModeSwitch: vi.fn().mockResolvedValue(undefined),
+			}),
+		}
+	})
+
+	it("should restore parent task mode when subtask completes", async () => {
+		// Create parent task with orchestrator mode
+		parentTask = new Task({
+			provider: mockProvider as any,
+			apiConfiguration: {} as any,
+			task: "Parent task",
+		})
+
+		// Set parent task to orchestrator mode
+		parentTask.pausedModeSlug = "orchestrator"
+
+		// Mock the provider reference
+		parentTask.providerRef = {
+			deref: () => mockProvider.deref(),
+		} as any
+
+		// Complete the subtask
+		await parentTask.completeSubtask("Subtask completed")
+
+		// Verify handleModeSwitch was called with the pausedModeSlug
+		expect(mockProvider.deref().handleModeSwitch).toHaveBeenCalledWith("orchestrator")
+
+		// Verify task is unpaused
+		expect(parentTask.isPaused).toBe(false)
+
+		// Verify childTaskId is cleared
+		expect(parentTask.childTaskId).toBeUndefined()
+	})
+
+	it("should handle missing provider gracefully", async () => {
+		// Create parent task
+		parentTask = new Task({
+			provider: mockProvider as any,
+			apiConfiguration: {} as any,
+			task: "Parent task",
+		})
+
+		// Set parent task to orchestrator mode
+		parentTask.pausedModeSlug = "orchestrator"
+
+		// Mock provider as unavailable
+		parentTask.providerRef = {
+			deref: () => undefined,
+		} as any
+
+		// Complete the subtask - should not throw
+		await expect(parentTask.completeSubtask("Subtask completed")).resolves.not.toThrow()
+
+		// Verify task is still unpaused
+		expect(parentTask.isPaused).toBe(false)
+	})
+})

src/core/webview/ClineProvider.ts

@@ -439,6 +439,9 @@ export class ClineProvider
 		// Resume the last cline instance in the stack (if it exists - this is
 		// the 'parent' calling task).
 		await this.getCurrentTask()?.completeSubtask(lastMessage)
+
+		// Explicitly trigger UI state update so that webview/pane transitions back to the parent thread.
+		await this.postStateToWebview()
 	}
 
 	/*