The most commonly encountered issue is not getting hits at empty spots. By default, clicks at areas with no content or background color are passed to its children (HitTestBehavior.deferToChild).

For example, a transparent container with a text at center will only respond to clicks if the text is hit, and not when the empty areas of the container are touched. Adding a behavior defines its true behavior. You can read more about this by following the link mentioned in the blog.