diff --git a/lib/Slic3r/Config.pm b/lib/Slic3r/Config.pm
index a0863ef8c..1cee4503a 100644
--- a/lib/Slic3r/Config.pm
+++ b/lib/Slic3r/Config.pm
@@ -120,7 +120,7 @@ our $Options = {
         cli     => 'extruder-offset=s@',
         type    => 'point',
         serialize   => sub { join ',', map { join 'x', @$_ } @{$_[0]} },
-        deserialize => sub { [ map [ split /x/, $_ ], (ref $_[0] eq 'ARRAY') ? @{$_[0]} : (split /,/, $_[0]) ] },
+        deserialize => sub { [ map [ split /x/, $_ ], (ref $_[0] eq 'ARRAY') ? @{$_[0]} : (split /,/, $_[0] || '0x0') ] },
         default => [[0,0]],
     },
     'nozzle_diameter' => {
diff --git a/lib/Slic3r/GUI/OptionsGroup.pm b/lib/Slic3r/GUI/OptionsGroup.pm
index de056cb8a..b7c562dc2 100644
--- a/lib/Slic3r/GUI/OptionsGroup.pm
+++ b/lib/Slic3r/GUI/OptionsGroup.pm
@@ -115,7 +115,7 @@ sub BUILD {
             }
             EVT_TEXT($self->parent, $_, sub { $self->_on_change($opt_key, [ $x_field->GetValue, $y_field->GetValue ]) })
                 for $x_field, $y_field;
-            $self->_setters->{$opt_key} = sub {
+            $self->_setters->{$opt_key} = sub {use XXX; ZZZ $_[0] if !defined $_[0][0];
                 $x_field->SetValue($_[0][0]);
                 $y_field->SetValue($_[0][1]);
             };