From cb35d1b4879f97b9b557eaf21e530898620e58aa Mon Sep 17 00:00:00 2001
From: Daniel Imms <2193314+Tyriar@users.noreply.github.com>
Date: Mon, 5 Jan 2026 12:31:54 -0800
Subject: [PATCH] Ensure mouse listeners are removed on dispose

Also use ? over ! just in case

Fixes #5586
---
 src/browser/CoreBrowserTerminal.ts | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/browser/CoreBrowserTerminal.ts b/src/browser/CoreBrowserTerminal.ts
index d2407062..abc363ed 100644
--- a/src/browser/CoreBrowserTerminal.ts
+++ b/src/browser/CoreBrowserTerminal.ts
@@ -636,8 +636,8 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
 
     // send event to CoreMouseService
     function sendEvent(ev: MouseEvent | WheelEvent): boolean {
-      // get mouse coordinates
-      const pos = self._mouseService!.getMouseReportCoords(ev, self.screenElement!);
+      // Get mouse coordinates
+      const pos = self._mouseService?.getMouseReportCoords(ev, self.screenElement!);
       if (!pos) {
         return false;
       }
@@ -804,6 +804,16 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
     // force initial onProtocolChange so we dont miss early mouse requests
     this.coreMouseService.activeProtocol = this.coreMouseService.activeProtocol;
 
+    // Ensure document-level listeners are removed on dispose
+    this._register(toDisposable(() => {
+      if (requestedEvents.mouseup) {
+        this._document!.removeEventListener('mouseup', requestedEvents.mouseup);
+      }
+      if (requestedEvents.mousedrag) {
+        this._document!.removeEventListener('mousemove', requestedEvents.mousedrag);
+      }
+    }));
+
     /**
      * "Always on" event listeners.
      */