In the Eden Editor Performance settings, under Dynamic Simulation → Activation Distance Settings, a description string is defined in the config but never appears in-game.

The vanilla config for this sub-category is:

class Cfg3DEN
{
    class Mission
    {
        class GarbageCollection
        {
            class AttributeCategories
            {
                class DynamicSimulation
                {
                    class Attributes
                    {
                        class DynSimSubCategory_ActivationDistances
                        {
                            data="AttributeSystemSubcategory";
                            control="SubCategory";
                            displayName="$STR_3DEN_dynsim_attributecategory_distances";
                            description="$STR_3DEN_dynsim_attributecategory_distances_desc";
                        };
                    };
                };
            };
        };
    };
};

Localization key STR_3DEN_dynsim_attributecategory_distances_desc exists and contains the text:

Set activation distances for each of the categories. Entities further away will not be simulated.

However, the SubCategory control is only capable of rendering a single line (displayName). It does not support the description field, so the string above is silently ignored and never shown to the user.

Config author clearly intended the description to be displayed, description property is defined with a existed localized string but SubCategory cannot render it. The correct control for a sub-category header with a description line could be SubCategoryDesc2, which explicitly supports descriptions with 2 lines.

Suggested fix:

class Cfg3DEN
{
    class Mission
    {
        class GarbageCollection
        {
            class AttributeCategories
            {
                class DynamicSimulation
                {
                    class Attributes
                    {
                        class DynSimSubCategory_ActivationDistances
                        {
                            control="SubCategory";
                            ↓↓↓
                            control="SubCategoryDesc2";
                        };
                    };
                };
            };
        };
    };
};

With this change, the existing description string will render correctly under the Activation Distance Settings header, as originally intended.

Additionals:

1. String fully translated:

               <Key ID="STR_3DEN_dynsim_attributecategory_distances_desc">
                 <Original>Set activation distances for each of the categories. Entities further away will not be simulated.</Original>
                 <English>Set activation distances for each of the categories. Entities further away will not be simulated.</English>
                 <Czech>Nastavuje vzdálenosti aktivace u každé kategorie. Vzdálenější entity nebudou simulovány.</Czech>
                 <German>Lege die Aktivierungsabstände für jede Kategorie fest. Weiter entfernte Entitäten werden nicht simuliert.</German>
                 <Russian>Задает расстояние активации для каждой из категорий. Более отдаленные элементы моделироваться не будут.</Russian>
                 <Polish>Określ odległość aktywacji dla poszczególnych kategorii. Bardziej oddalone jednostki nie będą symulowane.</Polish>
                 <Hungarian>Állítsd be az aktiválási távolságot minden kategóriához. A távolabbi entitások nem lesznek szimulálva.</Hungarian>
                 <Italian>Determina le distanze di attivazione per ciascuna categoria. Le entità più lontane non saranno simulate.</Italian>
                 <Spanish>Determina la distancia de activación de cada una de las categorías. Las entidades más lejanas no se simularán.</Spanish>
                 <French>Définit la distance d'activation de chaque catégorie. Les entités plus éloignées ne sont pas simulées.</French>
                 <Chinese>依據種類不同，設定啟動距離。超出距離外之物體不會模擬。</Chinese>
                 <Japanese>各カテゴリの起動距離を設定します。この距離の外にあるエンティティはシミュレートされません。</Japanese>
                 <Korean>각 범주별로 활성화 거리를 설정합니다. 멀리 있는 개체는 시뮬레이션되지 않습니다.</Korean>
                 <Portuguese>Defina as distâncias de ativação para cada uma das categorias. As entidades mais distantes não serão simuladas.</Portuguese>
                 <Chinesesimp>设置每个类别的激活距离。更远的实体将不被激活。</Chinesesimp>
                 <Turkish>Her kategori için etkinleşme mesafelerini ayarla. Uzaktaki varlıklar simüle edilmez.</Turkish>
                 <Latin>Distantias activationis pro singulis categoriis constitue. Entitates longius positae non simulabuntur.</Latin>
                 <Bulgarian>Задай дистанция на активиране за всяка категория. По-отдалечените обекти няма да се симулират.</Bulgarian>
                 <Slovak>Nastav vzdialenosti aktivácie pre každú kategóriu. Vzdialenejšie entity nebudú simulované.</Slovak>
                 <Ukrainian>Установи дистанцію активації для кожної категорії. Об'єкти, що далі, не симулюватимуться.</Ukrainian>
               </Key>

2. Full config patch:

   class Cfg3DEN
   {
   	class Mission
   	{
   		class GarbageCollection
   		{
   			class AttributeCategories
   			{
   				class DynamicSimulation
   				{
   					class Attributes
   					{
   						class DynSimSubCategory_ActivationDistances
   						{
   							control="SubCategoryDesc2";
   						};
   					};
   				};
   			};
   		};
   	};
   };