Added for all class items and subclass

module/data/item/base.mjs

@@ -8,6 +8,8 @@
  * @property {boolean} isInventoryItem- Indicates whether items of this type is a Inventory Item
  */
 
+import { addLinkedItemsDiff, updateLinkedItemApps } from '../../helpers/utils.mjs';
+
 const fields = foundry.data.fields;
 
 export default class BaseDataItem extends foundry.abstract.TypeDataModel {
@@ -153,30 +155,12 @@ export default class BaseDataItem extends foundry.abstract.TypeDataModel {
         const allowed = await super._preUpdate(changed, options, userId);
         if (allowed === false) return false;
 
-        if (changed.system?.features) {
+        addLinkedItemsDiff(changed.system?.features, this.features, options, 'changedFeatures');
-            const prevFeatures = new Set(this.features);
-            const newFeatures = new Set(changed.system.features);
-            options.changedFeatures = {
-                toLink: Array.from(newFeatures.difference(prevFeatures).map(feature => feature.item ?? feature)),
-                toUnlink: Array.from(
-                    prevFeatures.difference(newFeatures).map(feature => feature.item?.uuid ?? feature.uuid)
-                )
-            };
-        }
     }
 
     _onUpdate(changed, options, userId) {
         super._onUpdate(changed, options, userId);
 
-        if (options.changedFeatures) {
+        updateLinkedItemApps(options, 'changedFeatures', this.parent.sheet);
-            options.changedFeatures.toLink.forEach(featureUuid => {
-                const doc = foundry.utils.fromUuidSync(featureUuid);
-                doc.apps[this.parent.sheet.id] = this.parent.sheet;
-            });
-            options.changedFeatures.toUnlink.forEach(featureUuid => {
-                const doc = foundry.utils.fromUuidSync(featureUuid);
-                delete doc.apps[this.parent.sheet.id];
-            });
-        }
     }
 }

module/data/item/class.mjs

@@ -2,6 +2,7 @@ import BaseDataItem from './base.mjs';
 import ForeignDocumentUUIDField from '../fields/foreignDocumentUUIDField.mjs';
 import ForeignDocumentUUIDArrayField from '../fields/foreignDocumentUUIDArrayField.mjs';
 import ItemLinkFields from '../fields/itemLinkFields.mjs';
+import { addLinkedItemsDiff, updateLinkedItemApps } from '../../helpers/utils.mjs';
 
 export default class DHClass extends BaseDataItem {
     /** @inheritDoc */
@@ -96,4 +97,49 @@ export default class DHClass extends BaseDataItem {
             foundry.utils.getProperty(options.parent, `${path}.subclass`)?.delete();
         }
     }
+
+    async _preUpdate(changed, options, userId) {
+        const allowed = await super._preUpdate(changed, options, userId);
+        if (allowed === false) return false;
+
+        addLinkedItemsDiff(changed.system?.subclasses, this.subclasses, options, 'changedSubclasses');
+
+        const guide = changed.system?.characterGuide;
+        addLinkedItemsDiff(
+            guide?.suggestedPrimaryWeapon ? [guide.suggestedPrimaryWeapon] : null,
+            this.characterGuide.suggestedPrimaryWeapon ? [this.characterGuide.suggestedPrimaryWeapon] : [],
+            options,
+            'primaryWeapon'
+        );
+        addLinkedItemsDiff(
+            guide?.suggestedSecondaryWeapon ? [guide.suggestedSecondaryWeapon] : null,
+            this.characterGuide.suggestedSecondaryWeapon ? [this.characterGuide.suggestedSecondaryWeapon] : [],
+            options,
+            'secondaryWeapon'
+        );
+        addLinkedItemsDiff(
+            guide?.suggestedArmor ? [guide.suggestedArmor] : null,
+            this.characterGuide.suggestedArmor ? [this.characterGuide.suggestedArmor] : [],
+            options,
+            'armor'
+        );
+
+        addLinkedItemsDiff(changed.system?.inventory?.take, this.inventory.take, options, 'changedTake');
+        addLinkedItemsDiff(changed.system?.inventory?.choiceA, this.inventory.choiceA, options, 'changedChoiceA');
+        addLinkedItemsDiff(changed.system?.inventory?.choiceB, this.inventory.choiceB, options, 'changedChoiceB');
+    }
+
+    _onUpdate(changed, options, userId) {
+        super._onUpdate(changed, options, userId);
+
+        updateLinkedItemApps(options, 'changedSubclasses', this.parent.sheet);
+
+        updateLinkedItemApps(options, 'primaryWeapon', this.parent.sheet);
+        updateLinkedItemApps(options, 'secondaryWeapon', this.parent.sheet);
+        updateLinkedItemApps(options, 'armor', this.parent.sheet);
+
+        updateLinkedItemApps(options, 'changedTake', this.parent.sheet);
+        updateLinkedItemApps(options, 'changedChoiceA', this.parent.sheet);
+        updateLinkedItemApps(options, 'changedChoiceB', this.parent.sheet);
+    }
 }

module/helpers/utils.mjs

@@ -241,6 +241,45 @@ export function getDocFromElement(element) {
     return foundry.utils.fromUuidSync(target.dataset.itemUuid) ?? null;
 }
 
+/**
+ * Adds the update diff on a linkedItem property to update.options for use
+ * in _onUpdate via the updateLinkedItemApps function.
+ * @param {Array} changedItems            The candidate changed list
+ * @param {Array} currentItems            The current list
+ * @param {object} options                Additional options which modify the update request
+ * @param {string} optionsName            The name of the options property holding the diff
+ */
+export function addLinkedItemsDiff(changedItems, currentItems, options, optionsName) {
+    if (changedItems) {
+        const prevItems = new Set(currentItems);
+        const newItems = new Set(changedItems);
+        options[optionsName] = {
+            toLink: Array.from(newItems.difference(prevItems).map(item => item?.item ?? item)),
+            toUnlink: Array.from(prevItems.difference(newItems).map(item => item?.item?.uuid ?? item?.uuid ?? item))
+        };
+    }
+}
+
+/**
+ * Adds or removes the current Application from linked document apps
+ * depending on an update diff in the linked item list.
+ * @param {object} options                Additional options which modify the update requests
+ * @param {string} optionName             The prop name on options of the update diff
+ * @param {object} sheet                  The application to add or remove from document apps
+ */
+export function updateLinkedItemApps(options, optionName, sheet) {
+    if (options[optionName]) {
+        options[optionName].toLink.forEach(featureUuid => {
+            const doc = foundry.utils.fromUuidSync(featureUuid);
+            doc.apps[sheet.id] = sheet;
+        });
+        options[optionName].toUnlink.forEach(featureUuid => {
+            const doc = foundry.utils.fromUuidSync(featureUuid);
+            delete doc.apps[sheet.id];
+        });
+    }
+}
+
 export const itemAbleRollParse = (value, actor, item) => {
     if (!value) return value;
 

templates/sheets/items/class/settings.hbs

@@ -53,7 +53,7 @@
                 <legend>{{localize "DAGGERHEART.ITEMS.Class.guide.suggestedSecondaryWeaponTitle"}}</legend>
                 <div class="drop-section-body list-items">
                     {{#if document.system.characterGuide.suggestedSecondaryWeapon}}
-                        <div class="suggested-item item-line" data-action="editDoc" data-item-uuid="{{system.system.characterGuide.suggestedSecondaryWeapon.uuid}}">
+                        <div class="suggested-item item-line" data-action="editDoc" data-item-uuid="{{document.system.characterGuide.suggestedSecondaryWeapon.uuid}}">
                             <img class="image" src="{{document.system.characterGuide.suggestedSecondaryWeapon.img}}" />
                             <span>{{document.system.characterGuide.suggestedSecondaryWeapon.name}}</span>
                             <div class="controls">