remove default column and form field for enumerations of certain type

app/components/enumerations/table_component.rb

@@ -30,12 +30,15 @@
 
 module Enumerations
   class TableComponent < ::TableComponent
+    attr_reader :enumeration
+
+    def initialize(enumeration:, rows: [], **)
+      super(rows: rows, **)
+      @enumeration = enumeration
+    end
+
     def columns
-      %i[name is_default active sort].tap do |default|
-        if with_colors
-          default.insert 3, :color
-        end
-      end
+      headers.map(&:first)
     end
 
     def sortable?
@@ -43,16 +46,13 @@ module Enumerations
     end
 
     def headers
-      [
+      @headers ||= [
         ["name", { caption: Enumeration.human_attribute_name(:name) }],
-        ["is_default", { caption: Enumeration.human_attribute_name(:is_default) }],
+        enumeration.can_have_default_value? ? ["is_default", { caption: Enumeration.human_attribute_name(:is_default) }] : nil,
         ["active", { caption: Enumeration.human_attribute_name(:active) }],
+        with_colors ? ["color", { caption: Enumeration.human_attribute_name(:color) }] : nil,
         ["sort", { caption: I18n.t(:label_sort) }]
-      ].tap do |default|
-        if with_colors
-          default.insert 3, ["color", { caption: Enumeration.human_attribute_name(:color) }]
-        end
-      end
+      ].compact
     end
 
     def with_colors

app/models/enumeration.rb

@@ -75,6 +75,11 @@ class Enumeration < ApplicationRecord
     end
   end
 
+  # boolean to define if the enumeration can set a default
+  def self.can_have_default_value?
+    true
+  end
+
   # Destroys enumerations in a single transaction
   # It ensures, that the transactions can be safely transferred to each
   # entry's parent

app/views/enumerations/_form.html.erb

@@ -37,7 +37,10 @@ See COPYRIGHT and LICENSE files for more details.
   <%= f.hidden_field 'type' %>
   <div class="form--field -required"><%= f.text_field 'name', required: true, container_class: '-middle' %></div>
   <div class="form--field"><%= f.check_box 'active' %></div>
-  <div class="form--field"><%= f.check_box 'is_default' %></div>
+
+  <% if @enumeration.class.can_have_default_value? %>
+    <div class="form--field"><%= f.check_box 'is_default' %></div>
+  <% end %>
 
   <% if @enumeration.class.colored? %>
     <%= render partial: '/colors/color_autocomplete_field',

app/views/enumerations/index.html.erb

@@ -38,5 +38,5 @@ See COPYRIGHT and LICENSE files for more details.
 
 <% Enumeration.subclasses.each do |klass| %>
   <h3 class="-no-border"><%= t(klass::OptionName) %></h3>
-  <%= render(::Enumerations::TableComponent.new(rows: klass.shared)) %>
+  <%= render(::Enumerations::TableComponent.new(rows: klass.shared, enumeration: klass)) %>
 <% end %>

modules/costs/app/models/time_entry_activity.rb

@@ -64,6 +64,10 @@ class TimeEntryActivity < Enumeration
     Project.activated_time_activity(self)
   end
 
+  def self.can_have_default_value?
+    false
+  end
+
   private
 
   def detect_project_time_entry_activity_active_state(project)