fix top scrollbar freezing after card drag: re-resolve #board-container on rebuild, sync on parent; v1.4.2

Asset/js/top-scrollbar.js

@@ -10,6 +10,14 @@
  * track + thumb widget: it renders and behaves the same in every browser (Chrome, Firefox,
  * Safari) and on touch, and its thickness follows the --sv-bar-size setting.
  *
+ * Resilience note: after a card drag Kanboard rebuilds the board with
+ * `$("#board-container").replaceWith(data)` (BoardDragAndDrop.refresh), so the element we
+ * started with is destroyed and replaced. We therefore never cache the container: we
+ * re-resolve it on every use, listen for its scroll on `document` in the capture phase (so
+ * the listener survives the swap), and observe the STABLE parent (which is not replaced) so
+ * the widget keeps working -- previously the observer and scroll listener died with the old
+ * element, which froze the bar and lost sync after each move.
+ *
  * Loaded only when the "Add a top horizontal scrollbar" setting is enabled.
  */
 (function () {
@@ -18,14 +26,21 @@
     // Keep the thumb wide enough to grab, even on a very wide board.
     var MIN_THUMB = 24;
 
+    function getContainer() {
+        return document.getElementById("board-container");
+    }
+
     function init() {
-        var container = document.getElementById("board-container");
+        var container = getContainer();
 
         // Only on the board, and never add it twice.
         if (!container || document.querySelector(".sv-top-scroll")) {
             return;
         }
 
+        // The parent survives the board refresh (only #board-container is replaced).
+        var boardParent = container.parentNode;
+
         var track = document.createElement("div");
         track.className = "sv-top-scroll";
 
@@ -33,16 +48,21 @@
         thumb.className = "sv-top-scroll-thumb";
         track.appendChild(thumb);
 
-        container.parentNode.insertBefore(track, container);
+        boardParent.insertBefore(track, container);
 
         var dragging = false;
         var dragStartX = 0;
         var dragStartScrollLeft = 0;
 
         function metrics() {
+            var c = getContainer();
+            if (!c) {
+                return null;
+            }
             return {
-                viewport: container.clientWidth,
-                content: container.scrollWidth,
+                c: c,
+                viewport: c.clientWidth,
+                content: c.scrollWidth,
                 trackW: track.clientWidth
             };
         }
@@ -50,7 +70,7 @@
         function positionThumb(m, thumbW) {
             var maxScroll = m.content - m.viewport;
             var maxThumb = m.trackW - thumbW;
-            var left = maxScroll > 0 ? (container.scrollLeft / maxScroll) * maxThumb : 0;
+            var left = maxScroll > 0 ? (m.c.scrollLeft / maxScroll) * maxThumb : 0;
             thumb.style.transform = "translateX(" + Math.round(left) + "px)";
         }
 
@@ -58,7 +78,7 @@
         function layout() {
             var m = metrics();
 
-            if (m.content <= m.viewport || m.trackW <= 0) {
+            if (!m || m.content <= m.viewport || m.trackW <= 0) {
                 track.style.display = "none";
                 return;
             }
@@ -73,21 +93,33 @@
             positionThumb(m, thumbW);
         }
 
-        // Board scrolled by any other means -> keep the thumb in sync.
-        container.addEventListener("scroll", function () {
+        // Keep the track directly before the (current) container after a board refresh.
+        function reattachTrack() {
+            var c = getContainer();
+            if (c && c.parentNode && track.nextSibling !== c) {
+                c.parentNode.insertBefore(track, c);
+            }
+        }
+
+        // Board scrolled by any other means -> keep the thumb in sync. Capture-phase on
+        // document catches #board-container's (non-bubbling) scroll and survives the swap.
+        document.addEventListener("scroll", function (e) {
             if (dragging) { return; }
+            if (e.target !== getContainer()) { return; }
             var m = metrics();
-            if (m.content <= m.viewport) { return; }
+            if (!m || m.content <= m.viewport) { return; }
             positionThumb(m, thumb.offsetWidth);
-        });
+        }, true);
 
         // Drag the thumb (mouse + touch via Pointer Events).
         thumb.addEventListener("pointerdown", function (e) {
+            var c = getContainer();
+            if (!c) { return; }
             e.preventDefault();
             e.stopPropagation();
             dragging = true;
             dragStartX = e.clientX;
-            dragStartScrollLeft = container.scrollLeft;
+            dragStartScrollLeft = c.scrollLeft;
             track.classList.add("sv-dragging");
             if (thumb.setPointerCapture) {
                 thumb.setPointerCapture(e.pointerId);
@@ -97,10 +129,11 @@
         thumb.addEventListener("pointermove", function (e) {
             if (!dragging) { return; }
             var m = metrics();
+            if (!m) { return; }
             var maxThumb = m.trackW - thumb.offsetWidth;
             var maxScroll = m.content - m.viewport;
             if (maxThumb <= 0) { return; }
-            container.scrollLeft = dragStartScrollLeft + (e.clientX - dragStartX) * (maxScroll / maxThumb);
+            m.c.scrollLeft = dragStartScrollLeft + (e.clientX - dragStartX) * (maxScroll / maxThumb);
             positionThumb(m, thumb.offsetWidth);
         });
 
@@ -120,7 +153,7 @@
         track.addEventListener("pointerdown", function (e) {
             if (e.target === thumb || dragging) { return; }
             var m = metrics();
-            if (m.content <= m.viewport) { return; }
+            if (!m || m.content <= m.viewport) { return; }
 
             var thumbW = thumb.offsetWidth;
             var maxThumb = m.trackW - thumbW;
@@ -132,15 +165,19 @@
             if (targetLeft < 0) { targetLeft = 0; }
             if (targetLeft > maxThumb) { targetLeft = maxThumb; }
 
-            container.scrollLeft = (targetLeft / maxThumb) * maxScroll;
+            m.c.scrollLeft = (targetLeft / maxThumb) * maxScroll;
             positionThumb(m, thumbW);
         });
 
         window.addEventListener("resize", layout);
 
-        // The board can be redrawn by AJAX polling / drag-and-drop; keep sizes current.
+        // Observe the STABLE parent so we keep working after #board-container is replaced by
+        // a card move / AJAX polling; re-seat the track and recompute sizes on any change.
         if (window.MutationObserver) {
-            new MutationObserver(layout).observe(container, { childList: true, subtree: true });
+            new MutationObserver(function () {
+                reattachTrack();
+                layout();
+            }).observe(boardParent, { childList: true, subtree: true });
         }
 
         layout();

Plugin.php

@@ -51,7 +51,7 @@ class Plugin extends Base
 
     public function getPluginVersion()
     {
-        return '1.4.1';
+        return '1.4.2';
     }
 
     public function getPluginHomepage()

VERSION

@@ -1 +1 @@
-ShrinkVertically v1.4.1
+ShrinkVertically v1.4.2