allowShowingDuplicate property
By default, for every feature id, i.e. for every step in the feature discovery,
there can only be a single active overlay at a time as the default value
for allowShowingDuplicate is false.
This measure was taken primarily to prevent duplicate overlays from showing when the same widget is inserted into the widget tree multiple times, e.g. when there is an open DropdownButton.
If you want to display multiple overlays for the same step, i.e.
for the same feature id, at once, you will have to set this to true.
Implementation
final bool allowShowingDuplicate;