diff --git a/lib/Slic3r/Config.pm b/lib/Slic3r/Config.pm
index 22088ff3..5fba7b39 100644
--- a/lib/Slic3r/Config.pm
+++ b/lib/Slic3r/Config.pm
@@ -262,8 +262,6 @@ sub validate {
         if !first { $_ eq $self->solid_fill_pattern } @{$Options->{solid_fill_pattern}{values}};
     
     # --fill-density
-    die "Invalid value for --fill-density\n"
-        if $self->fill_density < 0 || $self->fill_density > 100;
     die "The selected fill pattern is not supposed to work at 100% density\n"
         if $self->fill_density == 100
             && !first { $_ eq $self->fill_pattern } @{$Options->{solid_fill_pattern}{values}};
diff --git a/lib/Slic3r/GUI/OptionsGroup.pm b/lib/Slic3r/GUI/OptionsGroup.pm
index c1cbe2d1..0b35dde6 100644
--- a/lib/Slic3r/GUI/OptionsGroup.pm
+++ b/lib/Slic3r/GUI/OptionsGroup.pm
@@ -171,19 +171,27 @@ sub _build_field {
         # default width on Windows is too large
         my $size = Wx::Size->new($opt->{width} || 60, $opt->{height} || -1);
         
-        $field = $opt->{type} eq 'i'
-            ? Wx::SpinCtrl->new($self->parent, -1, $opt->{default}, wxDefaultPosition, $size, $style, $opt->{min} || 0, $opt->{max} || 2147483647, $opt->{default})
-            : Wx::TextCtrl->new($self->parent, -1, $opt->{default}, wxDefaultPosition, $size, $style);
-        $field->Disable if $opt->{readonly};
-        
         my $on_change = sub { $self->_on_change($opt_key, $field->GetValue) };
         if ($opt->{type} eq 'i') {
+            $field = Wx::SpinCtrl->new($self->parent, -1, $opt->{default}, wxDefaultPosition, $size, $style, $opt->{min} || 0, $opt->{max} || 2147483647, $opt->{default});
             $self->_setters->{$opt_key} = sub { $field->SetValue($_[0]) };
             EVT_SPINCTRL ($self->parent, $field, $on_change);
+        } elsif ($opt->{values}) {
+            $field = Wx::ComboBox->new($self->parent, -1, $opt->{default}, wxDefaultPosition, $size, $opt->{labels} || $opt->{values});
+            $self->_setters->{$opt_key} = sub {
+                $field->SetValue($_[0]);
+            };
+            EVT_COMBOBOX($self->parent, $field, sub {
+                $field->SetValue($opt->{values}[ $field->GetSelection ]);  # set the text field to the selected value
+                $self->_on_change($opt_key, $on_change);
+            });
+            EVT_TEXT($self->parent, $field, $on_change);
         } else {
+            $field = Wx::TextCtrl->new($self->parent, -1, $opt->{default}, wxDefaultPosition, $size, $style);
             $self->_setters->{$opt_key} = sub { $field->ChangeValue($_[0]) };
             EVT_TEXT ($self->parent, $field, $on_change);
         }
+        $field->Disable if $opt->{readonly};
         $tooltip .= " (default: " . $opt->{default} .  ")" if ($opt->{default});
     } elsif ($opt->{type} eq 'bool') {
         $field = Wx::CheckBox->new($self->parent, -1, "");
diff --git a/xs/src/PrintConfig.hpp b/xs/src/PrintConfig.hpp
index b9fce0e6..096c7c7d 100644
--- a/xs/src/PrintConfig.hpp
+++ b/xs/src/PrintConfig.hpp
@@ -247,6 +247,34 @@ class PrintConfigDef
         Options["fill_density"].tooltip = "Density of internal infill, expressed in the range 0% - 100%.";
         Options["fill_density"].sidetext = "%";
         Options["fill_density"].cli = "fill-density=s";
+        Options["fill_density"].min = 0;
+        Options["fill_density"].max = 100;
+        Options["fill_density"].enum_values.push_back("5");
+        Options["fill_density"].enum_values.push_back("10");
+        Options["fill_density"].enum_values.push_back("15");
+        Options["fill_density"].enum_values.push_back("20");
+        Options["fill_density"].enum_values.push_back("25");
+        Options["fill_density"].enum_values.push_back("30");
+        Options["fill_density"].enum_values.push_back("40");
+        Options["fill_density"].enum_values.push_back("50");
+        Options["fill_density"].enum_values.push_back("60");
+        Options["fill_density"].enum_values.push_back("70");
+        Options["fill_density"].enum_values.push_back("80");
+        Options["fill_density"].enum_values.push_back("90");
+        Options["fill_density"].enum_values.push_back("100");
+        Options["fill_density"].enum_labels.push_back("5%");
+        Options["fill_density"].enum_labels.push_back("10%");
+        Options["fill_density"].enum_labels.push_back("15%");
+        Options["fill_density"].enum_labels.push_back("20%");
+        Options["fill_density"].enum_labels.push_back("25%");
+        Options["fill_density"].enum_labels.push_back("30%");
+        Options["fill_density"].enum_labels.push_back("40%");
+        Options["fill_density"].enum_labels.push_back("50%");
+        Options["fill_density"].enum_labels.push_back("60%");
+        Options["fill_density"].enum_labels.push_back("70%");
+        Options["fill_density"].enum_labels.push_back("80%");
+        Options["fill_density"].enum_labels.push_back("90%");
+        Options["fill_density"].enum_labels.push_back("100%");
 
         Options["fill_pattern"].type = coEnum;
         Options["fill_pattern"].label = "Fill pattern";