diff --git a/lib/Slic3r/Config.pm b/lib/Slic3r/Config.pm
index 514a45823d..256e6971c2 100644
--- a/lib/Slic3r/Config.pm
+++ b/lib/Slic3r/Config.pm
@@ -835,7 +835,9 @@ sub new_from_cli {
 
 sub merge {
     my $class = shift;
-    return $class->new(map %$_, @_);
+    my $config = $class->new;
+    $config->apply($_) for @_;
+    return $config;
 }
 
 sub load {
diff --git a/lib/Slic3r/GUI/SkeinPanel.pm b/lib/Slic3r/GUI/SkeinPanel.pm
index 5fbc8a2648..764f60a81f 100644
--- a/lib/Slic3r/GUI/SkeinPanel.pm
+++ b/lib/Slic3r/GUI/SkeinPanel.pm
@@ -232,16 +232,22 @@ sub config {
     
     # retrieve filament presets and build a single config object for them
     my $filament_config;
-    foreach my $preset_idx ($self->{plater}->filament_presets) {
-        my $preset = $self->{options_tabs}{filament}->get_preset($preset_idx);
-        my $config = $self->{options_tabs}{filament}->get_preset_config($preset);
-        if (!$filament_config) {
-            $filament_config = $config;
-            next;
-        }
-        foreach my $opt_key (keys %$config) {
-            next unless ref $filament_config->get($opt_key) eq 'ARRAY';
-            push @{ $filament_config->get($opt_key) }, $config->get($opt_key)->[0];
+    if ($self->{plater}->filament_presets == 1) {
+        $filament_config = $self->{options_tabs}{filament}->config;
+    } else {
+        # TODO: handle dirty presets.
+        # perhaps plater shouldn't expose dirty presets at all in multi-extruder environments.
+        foreach my $preset_idx ($self->{plater}->filament_presets) {
+            my $preset = $self->{options_tabs}{filament}->get_preset($preset_idx);
+            my $config = $self->{options_tabs}{filament}->get_preset_config($preset);
+            if (!$filament_config) {
+                $filament_config = $config;
+                next;
+            }
+            foreach my $opt_key (keys %$config) {
+                next unless ref $filament_config->get($opt_key) eq 'ARRAY';
+                push @{ $filament_config->get($opt_key) }, $config->get($opt_key)->[0];
+            }
         }
     }
     
diff --git a/lib/Slic3r/GUI/Tab.pm b/lib/Slic3r/GUI/Tab.pm
index 240963cddf..c0c7e52263 100644
--- a/lib/Slic3r/GUI/Tab.pm
+++ b/lib/Slic3r/GUI/Tab.pm
@@ -210,7 +210,8 @@ sub get_preset_config {
         }
         
         # apply preset values on top of defaults
-        $config->apply(Slic3r::Config->load($preset->{file}));
+        my $external_config = Slic3r::Config->load($preset->{file});
+        $config->set($_, $external_config->get($_)) for @{$self->{options}};
     }
     
     return $config;