This icon is a (non-selectable) status indicator. As soon as you
select a frame and see that this icon is shown in inverse video, it
means that a so-called text flow polygon
has been assigned to
it.
A text flow polygon is a vector frame with one or more vector
objects in it around which text will flow. This shape
can be
used as a text flow polygon in place of the normal rectangular frame.
A favourite application, for instance, is as a cut-out mask for a
scanned portrait photograph whose background should not be part of the
area that the text is to flow around.
As soon as a text flow polygon is assigned to a frame, its vector
path will be used for the text flow calculations – in place of
the actual frame, even if this frame has Automatic text flow
switched on.
You can assign a frame to a text flow polygon via the almost identical icon at the bottom of this function group. How this works is described below.
