The book "Mastering Perl/Tk" briefly introduces the canvas group item in chapter 9 (page 212ff).
There also is an example here: http://www.perlmonks.org/?node_id=602272
The documentation about the group item is missing in the POD of Tk::Canvas.
The group item type was invented by NI-S for Perl/Tk and is not part of Tcl/Tk. I agree, documentation about it would be nice, but we have to reverse engineer what this canvas item type is actually doing...
The book "Mastering Perl/Tk" briefly introduces the canvas group item in chapter 9 (page 212ff). There also is an example here: http://www.perlmonks.org/?node_id=602272
The documentation about the group item is missing in the POD of Tk::Canvas.
Could we please add it? Is it even a supported feature? I didn't find any information about it here: http://www.tcl.tk/man/tcl/TkCmd/canvas.htm