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  "title" : "splitView(_:shouldAdjustSizeOfSubview:)"
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# splitView(_:shouldAdjustSizeOfSubview:)

Allows the delegate to specify whether to resize the subview.

```
@MainActor optional func splitView(_ splitView: NSSplitView, shouldAdjustSizeOfSubview view: NSView) -> Bool
```

## Parameters

`splitView`

The split view that sends the message.

`view`

The subview to resize.

## Return Value

If [`adjustSubviews()`](/documentation/AppKit/NSSplitView/adjustSubviews()) can change the size of the subview, <doc://com.apple.documentation/documentation/Swift/true>; otherwise, <doc://com.apple.documentation/documentation/Swift/false>. By returning <doc://com.apple.documentation/documentation/Swift/false>, you lock the size of the split view `subview` while the split view resizes.

## Discussion

> Important:
> If your split view uses Auto Layout to size its subviews, don’t implement this method.

Regardless of the value that this method returns, [`adjustSubviews()`](/documentation/AppKit/NSSplitView/adjustSubviews()) may change the origin of the subview. Nonresizable subviews may resize to prevent an invalid subview layout.

If a split view has no delegate, or if its delegate doesn’t respond to this message, the split view behaves as if this method returns <doc://com.apple.documentation/documentation/Swift/true>.

---

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