Events & Hooks

Unified click & hover

Handler	Description
onGanttClick	Click on any timeline target
onGanttContextMenu	Right-click; call preventDefault() to suppress browser menu
onGanttHover	Hover on blocks, holidays, etc.

GanttTarget types

type	When	Key fields
task	Click bar or milestone	task, rowIndex, element
baseline	Click baseline marker	task, rowIndex
blockDate	Click blocked band	range, index
holiday	Click holiday band	date, label?
eventMarker	Click stripline	marker, index
draggableMarker	Click draggable marker	marker, index
timeline	Click empty area	date, rowIndex

<GanttChart
  blockDates={[{ start: '2026-04-14', end: '2026-04-16', label: 'Offsite' }]}
  onGanttContextMenu={(e) => {
    e.preventDefault();
    const { target } = e;
    if (target.type === 'task') openMenu(e.clientX, e.clientY, ['Edit', 'Delete'], target.task);
    if (target.type === 'timeline') openMenu(e.clientX, e.clientY, ['Add task'], target.date);
  }}
  onGanttHover={({ target, phase }) => {
    if (target?.type === 'blockDate' && phase === 'enter') showTip(target.range.label);
    if (phase === 'leave') hideTip();
  }}
/>

All event hooks

Prop	Event	Payload highlights
onTaskClick	taskClick	task, modifiers
onTaskDoubleClick	taskDoubleClick	task, rowIndex
onGanttClick	ganttClick	GanttPointerDetail
onGanttContextMenu	ganttContextMenu	GanttPointerDetail
onGanttHover	ganttHover	GanttHoverDetail
onTaskHover	taskHover	enter/leave only
onTaskDragStart/Drag/DragEnd	drag lifecycle	task, dates
onTaskResizeStart/Resize/ResizeEnd	resize lifecycle	task, edge
onProgressChange	progressChange	task, progress
onDraggableMarkerDragStart/Drag/DragEnd	marker drag lifecycle	marker, date, optional snapPoint
onDraggableMarkerDragToSnapPoint	marker snapped to custom point	snapPoint, phase: 'drag' | 'end'
onZoomChange	zoomChange	scaleId, columnWidth
onScroll	scroll	scrollLeft, scrollTop
onSidebarLayoutChange	layout	SidebarLayoutState
onSelectionChange	selection	{ selectedIds }
onTasksChange	—	Full GanttTask[] after edits

onTaskHover

Fires on enter and leave only — not on mousemove. Do not setState on every move from this hook.

See Advanced example and the GanttChart props reference.