Fix: dispatch interactive .kql queries to currently selected controller

src/extension/interactive/interactive.ts

@@ -15,7 +15,7 @@ import {
 } from 'vscode';
 import { commands } from 'vscode';
 import { InteractiveWindowView, registerDisposable } from '../utils';
-import { KernelPerConnection, registerController } from '../kernel/provider';
+import { getSelectedController, KernelPerConnection, registerController } from '../kernel/provider';
 import { FoldingRangesProvider } from '../languageServer';
 import { ensureDocumentHasConnectionInfo } from '../kusto/connections/notebookConnection';
 
@@ -69,11 +69,16 @@ async function executeSelectedQuery(document: TextDocument, start: number, end:
     if (!info) {
         return;
     }
-    const [notebook, controller] = info;
+    const [notebook, cachedController] = info;
     // Ensure its visible.
     await commands.executeCommand('interactive.open', undefined, notebook.uri, undefined);
     const cell = await createCell(notebook, document, start, end);
-    await controller.executeInteractive([cell], document);
+    // Prefer the controller currently selected on the interactive notebook so
+    // that if the user picked a different kernel in the window we honor it.
+    // Fall back to the originally-resolved controller in case the selection
+    // signal hasn't landed yet (e.g. first run before any onDidChangeSelectedNotebooks).
+    const activeController = getSelectedController(notebook) ?? cachedController;
+    await activeController.executeInteractive([cell], document);
 }
 
 async function pickConnection(document: TextDocument) {

src/extension/kernel/provider.ts

@@ -67,6 +67,15 @@ function getControllerId(connection: IConnectionInfo, notebookType: string) {
     return `${notebookType}_${encodeConnectionInfo(connection)}`;
 }
 
+// Currently-selected controller per notebook. Set by the
+// onDidChangeSelectedNotebooks handler below; used by `getSelectedController`
+// so callers can route execution to the kernel the user actually picked.
+const selectedControllerByNotebook = new WeakMap<NotebookDocument, KernelPerConnection>();
+
+export function getSelectedController(notebook: NotebookDocument): KernelPerConnection | undefined {
+    return selectedControllerByNotebook.get(notebook);
+}
+
 export class KernelPerConnection extends Disposable {
     public readonly notebookController: NotebookController;
     private readonly disposables: Disposable[] = [];
@@ -86,6 +95,13 @@ export class KernelPerConnection extends Disposable {
         this.notebookController.description = displayInfo.description;
         this.disposables.push(
             this.notebookController.onDidChangeSelectedNotebooks(async ({ notebook, selected }) => {
+                if (selected) {
+                    selectedControllerByNotebook.set(notebook, this);
+                } else if (selectedControllerByNotebook.get(notebook) === this) {
+                    // Only clear if we still own the slot — handles A→B switches
+                    // where B's `select` may fire before A's `deselect`.
+                    selectedControllerByNotebook.delete(notebook);
+                }
                 if (!selected) {
                     return;
                 }

src/extension/kusto/client.ts

@@ -1,5 +1,6 @@
 import type { KustoResponseDataSet } from 'azure-kusto-data';
 import { workspace, NotebookDocument, TextDocument } from 'vscode';
+import { isEqual } from 'lodash';
 // import { addDocumentConnectionHandler, ensureDocumentHasConnectionInfo } from './connections/notebookConnection';
 import { IConnection, IConnectionInfo, IKustoClient } from './connections/types';
 import { IDisposable } from '../types';
@@ -33,7 +34,17 @@ export class Client implements IDisposable {
     ): Promise<Client | undefined> {
         const client = clientMap.get(document);
         if (client) {
-            return client;
+            // If the caller specified a connection that doesn't match the cached
+            // client's connection (e.g. user switched kernel since last execution),
+            // drop the stale entry and recreate. Otherwise reuse.
+            if (!connectionInfo) {
+                return client;
+            }
+            const existing = await client;
+            if (existing && isEqual(existing.connectionInfo, connectionInfo)) {
+                return client;
+            }
+            clientMap.delete(document);
         }
 
         // eslint-disable-next-line no-async-promise-executor