always set lane

packages/z-timeline/lib/src/widgets/group_drop_target.dart

@@ -12,7 +12,10 @@ import 'timeline_view.dart';
 
 /// A drop target wrapper for a timeline group.
 ///
-/// Wraps group lanes content and handles drag-and-drop operations.
+/// Wraps the entire group column (header + lanes) and handles drag-and-drop
+/// operations. The [verticalOffset] accounts for the header height and padding
+/// so that lane calculations are correct relative to the lanes stack.
+///
 /// The ghost overlay is rendered by the parent widget in the same Stack.
 class GroupDropTarget extends StatelessWidget {
   const GroupDropTarget({
@@ -24,6 +27,7 @@ class GroupDropTarget extends StatelessWidget {
     required this.laneHeight,
     required this.lanesCount,
     required this.onEntryMoved,
+    required this.verticalOffset,
     required this.child,
     super.key,
   });
@@ -36,6 +40,11 @@ class GroupDropTarget extends StatelessWidget {
   final double laneHeight;
   final int lanesCount;
   final OnEntryMoved? onEntryMoved;
+
+  /// The vertical offset from the top of this widget to the top of the lanes
+  /// stack. This accounts for the group header height and any padding.
+  final double verticalOffset;
+
   final Widget child;
 
   @override
@@ -65,8 +74,12 @@ class GroupDropTarget extends StatelessWidget {
           viewport.end,
         );
 
+        // Subtract header + padding offset so Y is relative to the lanes stack.
+        // When the cursor is over the header, adjustedY is negative and clamps
+        // to lane 1.
+        final adjustedY = local.dy - verticalOffset;
         final rawLane = LayoutCoordinateService.yToLane(
-          y: local.dy,
+          y: adjustedY,
           laneHeight: laneHeight,
         );
         final maxAllowedLane = (lanesCount <= 0 ? 1 : lanesCount) + 1;

packages/z-timeline/lib/src/widgets/timeline_view.dart

@@ -84,7 +84,7 @@ class ZTimelineView extends StatelessWidget {
                     projected[group.id] ?? const <ProjectedEntry>[];
                 final lanesCount = _countLanes(groupEntries);
 
-                return Column(
+                final column = Column(
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
                     _GroupHeader(title: group.title, height: groupHeaderHeight),
@@ -98,11 +98,31 @@ class ZTimelineView extends StatelessWidget {
                       colorBuilder: colorBuilder,
                       labelBuilder: labelBuilder,
                       contentWidth: contentWidth,
-                      onEntryMoved: onEntryMoved,
                       enableDrag: enableDrag,
                     ),
                   ],
                 );
+
+                // Wrap the entire group (header + lanes) in a DragTarget
+                // so dragging over headers still updates the ghost position.
+                if (enableDrag && onEntryMoved != null) {
+                  return GroupDropTarget(
+                    group: group,
+                    entries: groupEntries,
+                    allEntries: entries,
+                    viewport: viewport,
+                    contentWidth: contentWidth,
+                    laneHeight: laneHeight,
+                    lanesCount: lanesCount,
+                    onEntryMoved: onEntryMoved,
+                    verticalOffset:
+                        groupHeaderHeight +
+                        ZTimelineConstants.verticalOuterPadding,
+                    child: column,
+                  );
+                }
+
+                return column;
               },
             );
           },
@@ -157,7 +177,6 @@ class _GroupLanes extends StatelessWidget {
     required this.labelBuilder,
     required this.colorBuilder,
     required this.contentWidth,
-    required this.onEntryMoved,
     required this.enableDrag,
   });
 
@@ -170,7 +189,6 @@ class _GroupLanes extends StatelessWidget {
   final EntryLabelBuilder labelBuilder;
   final EntryColorBuilder colorBuilder;
   final double contentWidth;
-  final OnEntryMoved? onEntryMoved;
   final bool enableDrag;
 
   @override
@@ -264,21 +282,6 @@ class _GroupLanes extends StatelessWidget {
       ),
     );
 
-    // Wrap with DragTarget if drag is enabled
-    if (enableDrag && onEntryMoved != null) {
-      innerStack = GroupDropTarget(
-        group: group,
-        entries: entries,
-        allEntries: allEntries,
-        viewport: viewport,
-        contentWidth: contentWidth,
-        laneHeight: laneHeight,
-        lanesCount: lanesCount,
-        onEntryMoved: onEntryMoved,
-        child: innerStack,
-      );
-    }
-
     return AnimatedSize(
       duration: const Duration(milliseconds: 150),
       curve: Curves.easeInOut,