Can't drag thumb icon when displayed inside formsheet (iOS 13)

[kfound]

Formsheets in iOS13 introduced the ability to drag the sheet down to dismiss it. This causes a problem with the GradientSlider where you can't drag the slider very far - it stutters and you'll see a call to cancelTracking invoked for seemingly no reason. If the GradientSlider is displayed in a popover; it works fine.

To fix the issue, you need to add code into the GradientSlider to ignore a UIPanGestureRecognizer:

override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        if gestureRecognizer is UIPanGestureRecognizer {
            return false
        }
        return true
}

You might also want to check isTracking == true but I found it didn't matter.

[alexanderconstancio]

Exactly what I needed thank you