With both the latest stable and beta versions of Flutter (1.2.1-stable and 1.4.9-hotfix.1), the iOS caret "handles" that allow to expand/shrink text selections on TextField widgets don't allow to drag the start handle when pressing and dragging the balloon at the top of the Start handle.

This can be reproduced with a simple app that just has a TextField widget.

The issue is the Gesture Detector widget is aligned with the top of the text field's text widget, while the caret handle is transformed to be higher. The GestureDetector should be transformed too.