The gesture is deliberately long: a short movement does nothing, so that a record is not deleted by an accidental touch. The mark lights up only when the gesture is long enough, and it means: let go here and the deletion starts.
Changed your mind - drag your finger back without letting go. The mark goes out and nothing happens.
The mark is a hint, not a button. There is no need to press it.
The gesture is the same as pressing the «Delete» button in the row and goes through the same checks. If deleting is not allowed - for example, the solution is filled into boxes, or your own box type is available on the Pro plan only - a window with the reason appears.
The gesture is a helper path. The button in the row stays where it was and works as before.