diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 4007d3a..aac55b6 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -123,6 +123,10 @@ module ApplicationHelper
     "Turbo.renderStreamMessage('#{j(render partial: partial, locals: locals)}'); return false;"
   end
 
+  def disabled_attributes(disabled)
+    disabled ? {disabled: true, aria: {disabled: true}, tabindex: -1} : {}
+  end
+
   private
 
   # Converts value to HTML formatted scientific notation
diff --git a/app/models/unit.rb b/app/models/unit.rb
index 872d0b7..29c05fb 100644
--- a/app/models/unit.rb
+++ b/app/models/unit.rb
@@ -57,13 +57,12 @@ class Unit < ApplicationRecord
             )
           ).as('portable')
         ),
-      # TODO: replace AS and MIN with Arel
-      # TODO: turn off ONLY_FULL_GROUP_BY
-      # Add missing base Units. Duplicates will be removed by final group(), as
-      # actionable Units will differ on 'portable' column and can't be UNION-ed.
+      # NOTE: turn off ONLY_FULL_GROUP_BY or is it incompatible with other DBs?
+      # Fill base Units to display proper hierarchy. Duplicates will be removed
+      # by final group() - can't be deduplicated with UNION due to 'portable' field.
       arel_table.join(actionable_units).on(actionable_units[:base_id].eq(arel_table[:id]))
-        .project(arel_table[Arel.star], 'NULL AS portable')
-    ]).select(units: column_names)#, 'MIN(units.portable)' => :portable)
+        .project(arel_table[Arel.star], Arel::Nodes.build_quoted(nil).as('portable'))
+    ]).select(units: column_names).select(units[:portable].minimum.as('portable'))
       .from(units).group(Unit.column_names)
   }
   scope :ordered, ->{
diff --git a/app/views/default/units/_unit.html.erb b/app/views/default/units/_unit.html.erb
index 19af7a3..1c1ec2d 100644
--- a/app/views/default/units/_unit.html.erb
+++ b/app/views/default/units/_unit.html.erb
@@ -1,20 +1,22 @@
 <%= tag.tr do %>
-  <td class="<%= class_names({subunit: unit.base, grayed: unit.default?}) %>">
+  <td class="<%= class_names({subunit: unit.base,
+                              grayed: unit.default? && !unit.portable.nil? }) %>">
     <%= unit.symbol %>
   </td>
 
   <td class="actions">
-    <% if current_user.at_least(:active) && unit.default? %>
-      <%= image_button_to t('.import'), 'download-outline', import_default_unit_path(unit),
-        !unit.portable? ? {disabled: true, aria: {disabled: true}, tabindex: -1} : {}  %>
-    <% end %>
-    <% if current_user.at_least(:admin) %>
-      <% if !unit.default? %>
-        <%= image_button_to t('.export'), 'upload-outline', export_default_unit_path(unit),
-          !unit.portable? ? {disabled: true, aria: {disabled: true}, tabindex: -1} : {}  %>
-      <% else %>
-        <%= image_button_to t('.delete'), 'delete-outline', unit_path(unit),
-          method: :delete %>
+    <% unless unit.portable.nil? %>
+      <% if current_user.at_least(:active) && unit.default? %>
+        <%= image_button_to t('.import'), 'download-outline', import_default_unit_path(unit),
+          disabled_attributes(!unit.portable?) %>
+      <% end %>
+      <% if current_user.at_least(:admin) %>
+        <% if unit.default? %>
+          <%= image_button_to t('.delete'), 'delete-outline', unit_path(unit), method: :delete %>
+        <% else %>
+          <%= image_button_to t('.export'), 'upload-outline', export_default_unit_path(unit),
+            disabled_attributes(!unit.portable?) %>
+        <% end %>
       <% end %>
     <% end %>
   </td>