diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9b2db972..13a56693 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -43,13 +43,29 @@ jobs:
     
     - name: Install dependencies
       run: npm install
-    
+
+    - name: Get installed Playwright version
+      id: playwright-version
+      run: echo "version=$(node -p 'require("@playwright/test/package.json").version')" >> "$GITHUB_OUTPUT"
+
+    - name: Cache Playwright browsers
+      id: playwright-cache
+      uses: actions/cache@v4
+      with:
+        path: ~/.cache/ms-playwright
+        key: playwright-${{ runner.os }}-${{ steps.playwright-version.outputs.version }}
+
     - name: Install Playwright browsers
+      if: steps.playwright-cache.outputs.cache-hit != 'true'
       run: npx playwright install --with-deps
-    
+
+    - name: Install Playwright system dependencies (cache hit)
+      if: steps.playwright-cache.outputs.cache-hit == 'true'
+      run: npx playwright install-deps
+
     - name: Build project
       run: npm run build
-    
+
     - name: Run E2E tests (all browsers, both builds)
       run: npm run test:e2e
     
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5064361f..eae513b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ All notable changes to this project will be documented here.
 
 ## [unreleased]
 
+## [0.23.5] - May 6th, 2026
+- Fix bug where on some browsers, middle-click-drag when annotations were vanished would trigger auto-scroll rather than the normal pan behavior.
+
 ## [0.23.4] - May 5th, 2026
 - Fix type declarations for npm consumers
 - Add `"files"` field to `package.json` to explicitly control published package contents.
diff --git a/package.json b/package.json
index c9e700e3..7af4ef34 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "ulabel",
   "description": "An image annotation tool.",
-  "version": "0.23.4",
+  "version": "0.23.5",
   "main": "dist/ulabel.min.js",
   "module": "dist/ulabel.min.js",
   "types": "index.d.ts",
diff --git a/src/index.js b/src/index.js
index fb1f7d36..3ed5acd5 100644
--- a/src/index.js
+++ b/src/index.js
@@ -5458,14 +5458,15 @@ export class ULabel {
     handle_mouse_down(mouse_event) {
         const drag_key = ULabel.get_drag_key_start(mouse_event, this);
         if (drag_key != null) {
+            // Suppress browser defaults (e.g. middle-click auto-scroll)
+            mouse_event.preventDefault();
             // Don't start new drag while id_dialog is visible or subtask is vanished
             if (
                 (this.get_current_subtask()["state"]["idd_visible"] && !this.get_current_subtask()["state"]["idd_thumbnail"]) ||
-                this.get_current_subtask()["state"]["is_vanished"]
+                (this.get_current_subtask()["state"]["is_vanished"] && drag_key !== "pan" && drag_key !== "zoom")
             ) {
                 return;
             }
-            mouse_event.preventDefault();
             if (this.drag_state["active_key"] === null) {
                 this.start_drag(drag_key, mouse_event.button, mouse_event);
             }
diff --git a/src/version.js b/src/version.js
index b27ead70..ea7e4054 100644
--- a/src/version.js
+++ b/src/version.js
@@ -1 +1 @@
-export const ULABEL_VERSION = "0.23.4";
+export const ULABEL_VERSION = "0.23.5";
diff --git a/tests/e2e/zoom-pan.spec.js b/tests/e2e/zoom-pan.spec.js
new file mode 100644
index 00000000..76346db5
--- /dev/null
+++ b/tests/e2e/zoom-pan.spec.js
@@ -0,0 +1,266 @@
+// End-to-end tests for zoom and pan interactions
+import { test, expect } from "./fixtures";
+import { wait_for_ulabel_init } from "../testing-utils/init_utils";
+
+/**
+ * Returns the current zoom_val from the ULabel instance.
+ * @param {import('@playwright/test').Page} page
+ */
+async function get_zoom_val(page) {
+    return await page.evaluate(() => window.ulabel.state.zoom_val);
+}
+
+/**
+ * Returns the current annbox scroll position {left, top}.
+ * @param {import('@playwright/test').Page} page
+ */
+async function get_annbox_scroll(page) {
+    return await page.evaluate(() => {
+        const annbox = document.getElementById(window.ulabel.config.annbox_id);
+        return { left: annbox.scrollLeft, top: annbox.scrollTop };
+    });
+}
+
+/**
+ * Returns the canvas element id for the current subtask.
+ * @param {import('@playwright/test').Page} page
+ */
+async function get_canvas_fid(page) {
+    return await page.evaluate(() => window.ulabel.get_current_subtask().canvas_fid);
+}
+
+/**
+ * Performs a click-drag from start to end with the given mouse button and
+ * optional modifier keys.
+ * @param {import('@playwright/test').Page} page
+ * @param {{x: number, y: number}} start
+ * @param {{x: number, y: number}} end
+ * @param {{button?: "left"|"middle"|"right", modifiers?: string[], steps?: number}} opts
+ */
+async function click_drag(page, start, end, opts = {}) {
+    const button = opts.button ?? "left";
+    const modifiers = opts.modifiers ?? [];
+    const steps = opts.steps ?? 10;
+
+    for (const mod of modifiers) {
+        await page.keyboard.down(mod);
+    }
+    await page.mouse.move(start.x, start.y);
+    await page.mouse.down({ button });
+    await page.mouse.move(end.x, end.y, { steps });
+    await page.mouse.up({ button });
+    for (const mod of modifiers) {
+        await page.keyboard.up(mod);
+    }
+}
+
+test.describe("Zoom and Pan Interactions", () => {
+    test("mouse wheel up zooms in", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        const initial_zoom = await get_zoom_val(page);
+
+        // Move into the annbox before scrolling
+        await page.mouse.move(400, 400);
+        await page.mouse.wheel(0, -100); // negative deltaY = zoom in
+        await page.waitForTimeout(50);
+
+        const new_zoom = await get_zoom_val(page);
+        expect(new_zoom).toBeGreaterThan(initial_zoom);
+    });
+
+    test("mouse wheel down zooms out", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        // Zoom in first so we have room to zoom out
+        await page.mouse.move(400, 400);
+        await page.mouse.wheel(0, -200);
+        await page.waitForTimeout(50);
+
+        const before_out = await get_zoom_val(page);
+
+        await page.mouse.wheel(0, 100); // positive deltaY = zoom out
+        await page.waitForTimeout(50);
+
+        const after_out = await get_zoom_val(page);
+        expect(after_out).toBeLessThan(before_out);
+    });
+
+    test("middle-click drag pans the annbox", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        // Zoom in so the image is larger than the viewport and can be panned
+        await page.mouse.move(400, 400);
+        await page.mouse.wheel(0, -300);
+        await page.waitForTimeout(50);
+
+        const before = await get_annbox_scroll(page);
+
+        // Drag from (500, 400) to (300, 250) — should pan the view
+        await click_drag(page, { x: 500, y: 400 }, { x: 300, y: 250 }, { button: "middle" });
+        await page.waitForTimeout(50);
+
+        const after = await get_annbox_scroll(page);
+        // Pan should change at least one of the scroll positions
+        expect(after.left !== before.left || after.top !== before.top).toBe(true);
+    });
+
+    test("ctrl+left-click drag on canvas pans the annbox", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        // Zoom in so we can pan
+        await page.mouse.move(400, 400);
+        await page.mouse.wheel(0, -300);
+        await page.waitForTimeout(50);
+
+        const canvas_fid = await get_canvas_fid(page);
+        const canvas = page.locator(`#${canvas_fid}`);
+        const box = await canvas.boundingBox();
+        expect(box).not.toBeNull();
+
+        const start = { x: box.x + box.width / 2, y: box.y + box.height / 2 };
+        const end = { x: start.x - 80, y: start.y - 60 };
+
+        const before = await get_annbox_scroll(page);
+        await click_drag(page, start, end, { button: "left", modifiers: ["Control"] });
+        await page.waitForTimeout(50);
+        const after = await get_annbox_scroll(page);
+
+        expect(after.left !== before.left || after.top !== before.top).toBe(true);
+    });
+
+    test("shift+left-click drag on canvas zooms", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        const canvas_fid = await get_canvas_fid(page);
+        const canvas = page.locator(`#${canvas_fid}`);
+        const box = await canvas.boundingBox();
+        expect(box).not.toBeNull();
+
+        const before_zoom = await get_zoom_val(page);
+
+        // Drag upward — drag_rezoom raises zoom when mouse moves up
+        const start = { x: box.x + box.width / 2, y: box.y + box.height / 2 };
+        const end = { x: start.x, y: start.y - 150 };
+
+        await click_drag(page, start, end, { button: "left", modifiers: ["Shift"] });
+        await page.waitForTimeout(50);
+
+        const after_zoom = await get_zoom_val(page);
+        expect(after_zoom).toBeGreaterThan(before_zoom);
+    });
+
+    test("shift+left-click drag still zooms when subtask is vanished", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        // Vanish the current subtask
+        await page.evaluate(() => {
+            window.ulabel.get_current_subtask().state.is_vanished = true;
+        });
+
+        const canvas_fid = await get_canvas_fid(page);
+        const canvas = page.locator(`#${canvas_fid}`);
+        const box = await canvas.boundingBox();
+        expect(box).not.toBeNull();
+
+        const before_zoom = await get_zoom_val(page);
+
+        const start = { x: box.x + box.width / 2, y: box.y + box.height / 2 };
+        const end = { x: start.x, y: start.y - 150 };
+
+        await click_drag(page, start, end, { button: "left", modifiers: ["Shift"] });
+        await page.waitForTimeout(50);
+
+        const after_zoom = await get_zoom_val(page);
+        expect(after_zoom).toBeGreaterThan(before_zoom);
+    });
+
+    test("middle-click drag still pans when subtask is vanished and does not start an annotation drag", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        // Zoom in so the image overflows the viewport (otherwise scroll positions
+        // cannot change anyway, which would make the assertion meaningless).
+        await page.mouse.move(400, 400);
+        await page.mouse.wheel(0, -300);
+        await page.waitForTimeout(50);
+
+        // Vanish the current subtask
+        await page.evaluate(() => {
+            window.ulabel.get_current_subtask().state.is_vanished = true;
+        });
+
+        // Record annotation count and observe drag_state.active_key during the drag
+        // by patching start_drag — this lets us catch any annotation drag that may
+        // start before mouseup clears active_key back to null.
+        const initial_annotation_count = await page.evaluate(() => {
+            const st = window.ulabel.get_current_subtask();
+            return Object.keys(st.annotations.access).length;
+        });
+        await page.evaluate(() => {
+            window.__observed_drag_keys = [];
+            const ul = window.ulabel;
+            const original_start_drag = ul.start_drag.bind(ul);
+            ul.start_drag = function (drag_key, mouse_button, mouse_event) {
+                window.__observed_drag_keys.push(drag_key);
+                return original_start_drag(drag_key, mouse_button, mouse_event);
+            };
+        });
+
+        const before = await get_annbox_scroll(page);
+        await click_drag(page, { x: 500, y: 400 }, { x: 300, y: 250 }, { button: "middle" });
+        await page.waitForTimeout(50);
+        const after = await get_annbox_scroll(page);
+
+        // Pan must have moved the annbox scroll position
+        expect(after.left !== before.left || after.top !== before.top).toBe(true);
+
+        // Only a "pan" drag should have started — no annotation drag
+        const observed = await page.evaluate(() => window.__observed_drag_keys);
+        expect(observed).toEqual(["pan"]);
+
+        // No annotation should have been created
+        const final_annotation_count = await page.evaluate(() => {
+            const st = window.ulabel.get_current_subtask();
+            return Object.keys(st.annotations.access).length;
+        });
+        expect(final_annotation_count).toBe(initial_annotation_count);
+    });
+
+    test("annotation drag is blocked when subtask is vanished", async ({ page }) => {
+        await wait_for_ulabel_init(page);
+
+        // Ensure bbox mode
+        await page.click("a#md-btn--bbox");
+        await page.waitForTimeout(50);
+
+        // Vanish the current subtask
+        await page.evaluate(() => {
+            window.ulabel.get_current_subtask().state.is_vanished = true;
+        });
+
+        const initial_count = await page.evaluate(() => {
+            const st = window.ulabel.get_current_subtask();
+            return Object.keys(st.annotations.access).length;
+        });
+
+        // Attempt to draw a bbox via plain left-drag on the canvas
+        const canvas_fid = await get_canvas_fid(page);
+        const canvas = page.locator(`#${canvas_fid}`);
+        const box = await canvas.boundingBox();
+        const start = { x: box.x + box.width / 2 - 60, y: box.y + box.height / 2 - 40 };
+        const end = { x: start.x + 120, y: start.y + 80 };
+        await click_drag(page, start, end, { button: "left" });
+        await page.waitForTimeout(100);
+
+        // No annotation should have been created — annotation drags are blocked while vanished
+        const final_count = await page.evaluate(() => {
+            const st = window.ulabel.get_current_subtask();
+            return Object.keys(st.annotations.access).length;
+        });
+        expect(final_count).toBe(initial_count);
+
+        // drag_state.active_key should still be null
+        const active_key = await page.evaluate(() => window.ulabel.drag_state.active_key);
+        expect(active_key).toBeNull();
+    });
+});