Picker rows disappear when scrolling

When I try to scroll through my picker which is positioned under the title all the rows disappear. I have searched for this issue and I have found (not here) that the issue is connected with the view that contains the picker.

Are there any solutions?

my code:

```
import BLTNBoard

class PickerBLTNItem: BLTNPageItem, UIPickerViewDataSource, UIPickerViewDelegate {
lazy var picker: UIPickerView = UIPickerView()
var items: [T]

init(items: [T]) {
self.items = items
super.init(title: T.description)
setup()
}

func setup() {
image = T.image
actionButtonTitle = Localized.General.done
picker.delegate = self
picker.dataSource = self
}

override func makeViewsUnderImage(with interfaceBuilder: BLTNInterfaceBuilder) -> [UIView]? {
return [picker]
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return items[row].description
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return items.count
}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
}
```

first I have tried implementing a picker with custom rows and I thought that the customization might cause this problem but even the simplest picker implementation doesn't work and causes the same issue.