my $opt_frame = $pop->Frame(
    -bg => 'grey',
    -width => '300',
    -height => '20'
)->pack();

$page1->Label(-text=>'Benachrichtigungen')->grid(-row=>'0', -column=>'0',-in=> $opt_frame);

Tk::Error: can't put .toplevel.notebook.pageID_1.label inside .toplevel.frame at
 C:/Perl/site/lib/Tk/Widget.pm line 1072, <DATA> line 164.
 Tk callback for grid
 [\&main::]
 (menu invoke)