---
title: "outlineView(_:toolTipFor:rect:tableColumn:item:mouseLocation:)"
framework: appkit
role: symbol
role_heading: Instance Method
path: "appkit/nsoutlineviewdelegate/outlineview(_:tooltipfor:rect:tablecolumn:item:mouselocation:)"
---

# outlineView(_:toolTipFor:rect:tableColumn:item:mouseLocation:)

When the cursor pauses over a given cell, the value returned from this method is displayed in a tooltip.

## Declaration

```swift
@MainActor optional func outlineView(_ outlineView: NSOutlineView, toolTipFor cell: NSCell, rect: NSRectPointer, tableColumn: NSTableColumn?, item: Any, mouseLocation: NSPoint) -> String
```

## Parameters

- `outlineView`: The outline view that sent the message.
- `cell`: The cell for which to generate a tooltip.
- `rect`: The proposed active area of the tooltip. To control the default active area, you can modify the rect parameter. By default, rect is computed as [cell drawingRectForBounds:cellFrame].
- `tableColumn`: The table column that contains cell.
- `item`: The item for which to display a tooltip.
- `mouseLocation`: The current mouse location in view coordinates.

## Return Value

Return Value If you don’t want a tooltip at that location, return an empty string.