accept custom widgets as classes instead of instances, #4274

src/public/app/services/bundle.js

@@ -53,7 +53,15 @@ class WidgetsByParent {
     }
 
     get(parentName) {
-        return this.byParent[parentName] || [];
+        if (!this.byParent[parentName]) {
+            return [];
+        }
+
+        return this.byParent[parentName]
+            // previously, custom widgets were provided as a single instance, but that has the disadvantage
+            // for splits where we actually need multiple instaces and thus having a class to instantiate is better
+            // https://github.com/zadam/trilium/issues/4274
+            .map(w => w.prototype ? new w() : w);
     }
 }