From fce467fa8711fb4a5d961a5f7975ae3121250236 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrgen=20Mummert?= <juergen@MacBookPro.fritz.box>
Date: Mon, 23 Feb 2026 20:00:36 +0100
Subject: [PATCH] Harden SlimSelect scroll lock on macOS browsers

---
 .../templates/frontend/event_filter.html.twig | 71 ++++++++++++++++---
 1 file changed, 61 insertions(+), 10 deletions(-)

diff --git a/contao/templates/frontend/event_filter.html.twig b/contao/templates/frontend/event_filter.html.twig
index 894a266..4e4331b 100644
--- a/contao/templates/frontend/event_filter.html.twig
+++ b/contao/templates/frontend/event_filter.html.twig
@@ -342,17 +342,57 @@
             return null;
         }
 
-        return target.closest('#eventfilters .ss-content, #eventfilters .ss-list');
+        return target.closest('.ss-content, .ss-list');
     };
 
-    const shouldBlockBoundaryScroll = (dropdown, delta) => {
-        if (!dropdown || dropdown.scrollHeight <= dropdown.clientHeight) {
+    const getOpenDropdown = () => {
+        const openContent = document.querySelector('.ss-content.ss-open');
+
+        if (openContent) {
+            return openContent;
+        }
+
+        const openMain = document.querySelector('.ss-main.ss-open');
+
+        if (!openMain) {
+            return null;
+        }
+
+        const scope = openMain.parentElement || document;
+        return scope.querySelector('.ss-content');
+    };
+
+    const getScrollContainer = (targetDropdown) => {
+        const openDropdown = getOpenDropdown();
+
+        if (!openDropdown) {
+            return null;
+        }
+
+        if (!targetDropdown) {
+            return openDropdown;
+        }
+
+        const contentContainer = targetDropdown.closest('.ss-content');
+        return contentContainer || openDropdown;
+    };
+
+    const shouldBlockBoundaryScroll = (scrollContainer, delta) => {
+        if (!scrollContainer) {
             return false;
         }
 
-        const top = dropdown.scrollTop;
-        const height = dropdown.clientHeight;
-        const scrollHeight = dropdown.scrollHeight;
+        if (scrollContainer.scrollHeight <= scrollContainer.clientHeight) {
+            return true;
+        }
+
+        if (delta === 0) {
+            return false;
+        }
+
+        const top = scrollContainer.scrollTop;
+        const height = scrollContainer.clientHeight;
+        const scrollHeight = scrollContainer.scrollHeight;
 
         const atTop = top <= 0;
         const atBottom = top + height >= scrollHeight - 1;
@@ -364,16 +404,24 @@
 
     document.addEventListener('wheel', (event) => {
         const dropdown = getDropdownFromTarget(event.target);
+        const scrollContainer = getScrollContainer(dropdown);
 
-        if (shouldBlockBoundaryScroll(dropdown, event.deltaY)) {
+        if (!scrollContainer) {
+            return;
+        }
+
+        if (shouldBlockBoundaryScroll(scrollContainer, event.deltaY)) {
             event.preventDefault();
         }
+
+        event.stopPropagation();
     }, { passive: false, capture: true });
 
     document.addEventListener('touchstart', (event) => {
         const dropdown = getDropdownFromTarget(event.target);
+        const scrollContainer = getScrollContainer(dropdown);
 
-        if (!dropdown || event.touches.length === 0) {
+        if (!scrollContainer || event.touches.length === 0) {
             lastTouchY = null;
             return;
         }
@@ -383,18 +431,21 @@
 
     document.addEventListener('touchmove', (event) => {
         const dropdown = getDropdownFromTarget(event.target);
+        const scrollContainer = getScrollContainer(dropdown);
 
-        if (!dropdown || event.touches.length === 0 || lastTouchY === null) {
+        if (!scrollContainer || event.touches.length === 0 || lastTouchY === null) {
             return;
         }
 
         const currentTouchY = event.touches[0].clientY;
         const delta = lastTouchY - currentTouchY;
 
-        if (shouldBlockBoundaryScroll(dropdown, delta)) {
+        if (shouldBlockBoundaryScroll(scrollContainer, delta)) {
             event.preventDefault();
         }
 
+        event.stopPropagation();
+
         lastTouchY = currentTouchY;
     }, { passive: false, capture: true });