diff --git a/ui/src/pages/IssueDetail.test.tsx b/ui/src/pages/IssueDetail.test.tsx
index 36ea52e93e..4a59314de6 100644
--- a/ui/src/pages/IssueDetail.test.tsx
+++ b/ui/src/pages/IssueDetail.test.tsx
@@ -2136,6 +2136,8 @@ describe("IssueDetail", () => {
     );
     expect(panel).not.toBeNull();
     expect(panel?.className).toContain("max-h-(--sz-85dvh)");
+    expect(panel?.className).toContain("w-full");
+    expect(panel?.className).toContain("max-w-none");
     expect(panel?.textContent).toContain("Task side panel");
     expect(panel?.querySelector('[data-slot="sheet-close"]')).not.toBeNull();
   });
diff --git a/ui/src/pages/IssueDetail.tsx b/ui/src/pages/IssueDetail.tsx
index ffce188be9..b85b20b97d 100644
--- a/ui/src/pages/IssueDetail.tsx
+++ b/ui/src/pages/IssueDetail.tsx
@@ -8060,7 +8060,7 @@ export function IssueDetail({ tasksTab }: { tasksTab?: TaskSidePanelProps["tasks
               showCloseButton={!taskChatShellEnabled}
               className={cn(
                 taskChatShellEnabled
-                  ? "h-(--sz-85dvh) max-h-(--sz-85dvh) gap-0 p-0 pb-(--sz-safe-bottom)"
+                  ? "h-(--sz-85dvh) max-h-(--sz-85dvh) w-full max-w-none gap-0 p-0 pb-(--sz-safe-bottom)"
                   : documentDeepLink?.documentKey === "plan"
                     ? "inset-0 h-dvh w-screen max-w-none gap-0 border-0 p-0 sm:max-w-none"
                     : "max-h-(--sz-85dvh) pb-(--sz-safe-bottom)",