Workaround for Wx/GTK bug on Linux

lib/Slic3r/GUI/OptionsGroup.pm

@@ -17,6 +17,7 @@ sub new {
     
     foreach my $opt (@{$p{options}}) {
         my $label = Wx::StaticText->new($parent, -1, "$opt->{label}:", Wx::wxDefaultPosition, [180,-1]);
+        $label->Wrap(180);  # needed to avoid Linux/GTK bug
         my $field;
         if ($opt->{type} =~ /^(i|f)$/) {
             $field = Wx::TextCtrl->new($parent, -1, ${$opt->{value}});

lib/Slic3r/GUI/SkeinPanel.pm

@@ -199,7 +199,6 @@ sub new {
     );
     
     $panels{slice} = Wx::BoxSizer->new(wxVERTICAL);
-    $panels{slice}->Add(-1, 20);  # empty space before button
     my $slice_button = Wx::Button->new($self, -1, "Slice...");
     $panels{slice}->Add($slice_button, 0, wxALIGN_CENTER);
     EVT_BUTTON($self, $slice_button, \&do_slice);