From e104d47dc11e057bfa6cedd77a6cc8852dfc73de Mon Sep 17 00:00:00 2001
From: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>
Date: Fri, 19 Jun 2026 15:01:22 +0100
Subject: [PATCH] fix(viewer): always restore text selection when pan is
 toggled off

---
 .../core/components/viewer/PanAPIBridge.tsx   | 39 +++++++++++++------
 .../viewer/useViewerWorkbenchBarButtons.tsx   |  8 ++--
 2 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/frontend/editor/src/core/components/viewer/PanAPIBridge.tsx b/frontend/editor/src/core/components/viewer/PanAPIBridge.tsx
index 772af6d5ac..9d9b09fb61 100644
--- a/frontend/editor/src/core/components/viewer/PanAPIBridge.tsx
+++ b/frontend/editor/src/core/components/viewer/PanAPIBridge.tsx
@@ -1,5 +1,6 @@
 import { useEffect, useRef } from "react";
 import { usePan } from "@embedpdf/plugin-pan/react";
+import { useInteractionManagerCapability } from "@embedpdf/plugin-interaction-manager/react";
 import { useViewer } from "@app/contexts/ViewerContext";
 import { useActiveDocumentId } from "@app/components/viewer/useActiveDocumentId";
 import { useDocumentReady } from "@app/components/viewer/hooks/useDocumentReady";
@@ -21,13 +22,18 @@ export function PanAPIBridge() {
 
 function PanAPIBridgeInner({ documentId }: { documentId: string }) {
   const { provides: pan, isPanning } = usePan(documentId);
+  const { provides: imCapability } = useInteractionManagerCapability();
   const { registerBridge, triggerImmediatePanUpdate } = useViewer();
 
-  // Keep pan ref updated to avoid re-running effect when object reference changes
+  // Keep refs updated to avoid re-running effect when object references change
   const panRef = useRef(pan);
   useEffect(() => {
     panRef.current = pan;
   }, [pan]);
+  const imRef = useRef(imCapability);
+  useEffect(() => {
+    imRef.current = imCapability;
+  }, [imCapability]);
 
   // Track previous isPanning value to detect changes
   const prevIsPanningRef = useRef<boolean>(isPanning);
@@ -39,6 +45,17 @@ function PanAPIBridgeInner({ documentId }: { documentId: string }) {
         isPanning,
       };
 
+      // Pan off must always land in selection (pointerMode), not the default mode -
+      // if pan ever became the default, disablePan/togglePan couldn't escape it (#5175).
+      const goToPointerMode = () => {
+        const im = imRef.current;
+        if (im) {
+          im.forDocument(documentId).activate("pointerMode");
+        } else {
+          currentPan.disablePan();
+        }
+      };
+
       // Register this bridge with ViewerContext
       registerBridge("pan", {
         state: newState,
@@ -47,22 +64,20 @@ function PanAPIBridgeInner({ documentId }: { documentId: string }) {
             currentPan.enablePan();
           },
           disable: () => {
-            currentPan.disablePan();
+            goToPointerMode();
           },
           toggle: () => {
-            currentPan.togglePan();
-          },
-          makePanDefault: () => {
-            // v2.5.0: makePanDefault may not exist, enable pan as fallback
-            if (
-              "makePanDefault" in currentPan &&
-              typeof (currentPan as any).makePanDefault === "function"
-            ) {
-              (currentPan as any).makePanDefault();
+            if (isPanning) {
+              goToPointerMode();
             } else {
               currentPan.enablePan();
             }
           },
+          makePanDefault: () => {
+            // Never make pan the default mode (that is what locks the viewer in
+            // #5175). Just enable pan for the current interaction.
+            currentPan.enablePan();
+          },
         },
       });
 
@@ -75,7 +90,7 @@ function PanAPIBridgeInner({ documentId }: { documentId: string }) {
     return () => {
       registerBridge("pan", null);
     };
-  }, [isPanning, registerBridge, triggerImmediatePanUpdate]);
+  }, [isPanning, registerBridge, triggerImmediatePanUpdate, documentId]);
 
   return null;
 }
diff --git a/frontend/editor/src/core/components/viewer/useViewerWorkbenchBarButtons.tsx b/frontend/editor/src/core/components/viewer/useViewerWorkbenchBarButtons.tsx
index 4960672dd9..53669424f0 100644
--- a/frontend/editor/src/core/components/viewer/useViewerWorkbenchBarButtons.tsx
+++ b/frontend/editor/src/core/components/viewer/useViewerWorkbenchBarButtons.tsx
@@ -211,12 +211,10 @@ export function useViewerWorkbenchBarButtons(
         disabled:
           !isPanning && pendingCount > 0 && redactionActiveType !== null,
         onClick: () => {
+          // Don't optimistically flip isPanning - it must reflect the real EmbedPDF
+          // mode so the button can't show "off" while still stuck in pan (#5175).
           viewer.panActions.togglePan();
-          setIsPanning((prev) => {
-            const next = !prev;
-            if (next && isRulerActive) setIsRulerActive?.(false);
-            return next;
-          });
+          if (!isPanning && isRulerActive) setIsRulerActive?.(false);
         },
       },
       {