Strange tall cursor (sometimes) using mouse with iPad?

I just recently connected an Apple Magic Mouse (1st gen) to my iPad. Usually, in most areas of my Calc sheets, the mouse cursor is the usual iPad transparent center circle, changing shape a bit to outline larger icons in the controls sections. But sometimes, after clicking or double-clicking in some data cells, it becomes a tall narrow loop, and stays that way all over the screen until I click in a different cell:

Does this have a purpose?