fix: notif list viewport jumping around on delegate creation

modules/sidebar/NotifDockList.qml

@@ -22,6 +22,7 @@ LazyListView {
     cacheBuffer: 400
     asynchronous: true
 
+    onViewportAdjustNeeded: d => container.contentY += d
     useCustomViewport: true
     viewport: Qt.rect(0, container.contentY, width, container.height)
 
@@ -66,6 +67,7 @@ LazyListView {
                 clearTimer.start();
             }
 
+            LazyListView.trackViewport: notifInner.expanded || notifInner.nonAnimHeight < notifInner.implicitHeight
             LazyListView.preferredHeight: closed ? 0 : notifInner.nonAnimHeight
             LazyListView.visibleHeight: notifInner.implicitHeight
             implicitHeight: notifInner.implicitHeight

plugin/src/Caelestia/Components/lazylistview.cpp

@@ -62,6 +62,17 @@ void LazyListViewAttached::setRemoving(bool removing) {
     emit removingChanged();
 }
 
+bool LazyListViewAttached::trackViewport() const {
+    return m_trackViewport;
+}
+
+void LazyListViewAttached::setTrackViewport(bool track) {
+    if (m_trackViewport == track)
+        return;
+    m_trackViewport = track;
+    emit trackViewportChanged();
+}
+
 // --- LazyListView ---
 
 LazyListView::LazyListView(QQuickItem* parent)
@@ -628,11 +639,21 @@ void LazyListView::syncDelegates() {
         if (entry.item) {
             const qreal h = delegateHeight(entry.item);
             if (!m_layout[i].heightKnown || !qFuzzyCompare(m_layout[i].height + 1.0, h + 1.0)) {
+                const qreal oldLayoutH = m_layout[i].heightKnown ? m_layout[i].height : effectiveEstimatedHeight();
                 if (m_layout[i].heightKnown)
                     untrackHeight(m_layout[i].height);
                 m_layout[i].height = h;
                 m_layout[i].heightKnown = true;
                 trackHeight(h);
+
+                // Compensate if tracked item materializes above viewport
+                auto* att =
+                    qobject_cast<LazyListViewAttached*>(qmlAttachedPropertiesObject<LazyListView>(entry.item, false));
+                if (att && att->trackViewport()) {
+                    const qreal vpTop = m_useCustomViewport ? m_viewport.y() : m_contentY;
+                    if (m_layout[i].targetY < vpTop)
+                        emit viewportAdjustNeeded(h - oldLayoutH);
+                }
                 layoutChanged = true;
             }
             entry.item->setY(m_layout[i].targetY - m_contentY);
@@ -745,6 +766,18 @@ LazyListView::DelegateEntry LazyListView::createDelegate(int modelIndex) {
             if (wasKnown)
                 untrackHeight(oldH);
             trackHeight(h);
+
+            // If this tracked item is above the viewport, emit a
+            // compensation delta so the consumer can adjust scroll.
+            if (wasKnown) {
+                auto* att = qobject_cast<LazyListViewAttached*>(qmlAttachedPropertiesObject<LazyListView>(item, false));
+                if (att && att->trackViewport()) {
+                    const qreal vpTop = m_useCustomViewport ? m_viewport.y() : m_contentY;
+                    if (m_layout[idx].targetY < vpTop)
+                        emit viewportAdjustNeeded(h - oldH);
+                }
+            }
+
             if (!m_relayoutPending) {
                 m_relayoutPending = true;
                 QTimer::singleShot(0, this, [this] {

plugin/src/Caelestia/Components/lazylistview.hpp

@@ -21,6 +21,7 @@ class LazyListViewAttached : public QObject {
     Q_PROPERTY(qreal visibleHeight READ visibleHeight WRITE setVisibleHeight NOTIFY visibleHeightChanged)
     Q_PROPERTY(bool adding READ adding NOTIFY addingChanged)
     Q_PROPERTY(bool removing READ removing NOTIFY removingChanged)
+    Q_PROPERTY(bool trackViewport READ trackViewport WRITE setTrackViewport NOTIFY trackViewportChanged)
 
 public:
     explicit LazyListViewAttached(QObject* parent = nullptr);
@@ -37,17 +38,22 @@ public:
     [[nodiscard]] bool removing() const;
     void setRemoving(bool removing);
 
+    [[nodiscard]] bool trackViewport() const;
+    void setTrackViewport(bool track);
+
 signals:
     void preferredHeightChanged();
     void visibleHeightChanged();
     void addingChanged();
     void removingChanged();
+    void trackViewportChanged();
 
 private:
     qreal m_preferredHeight = -1;
     qreal m_visibleHeight = -1;
     bool m_adding = false;
     bool m_removing = false;
+    bool m_trackViewport = false;
 };
 
 class LazyListView : public QQuickItem {
@@ -198,6 +204,7 @@ signals:
     void moveCurveChanged();
     void countChanged();
     void settledChanged();
+    void viewportAdjustNeeded(qreal delta);
 
 protected:
     void componentComplete() override;