frontend/src/features/lists/SharedListsView.tsx

@@ -529,6 +529,8 @@ export const SharedListsView: React.FC<SharedListsViewProps> = ({ onRefreshGloba
             const isShared =
               (activeSpace.shares && activeSpace.shares.length > 0) ||
               (activeSpace.members && activeSpace.members.length > 1);
+            const ownerMember = activeSpace.members?.find((m) => m.role === 'owner' || m.userId === activeSpace.ownerId);
+            const ownerDisplayName = activeSpace.ownerName || ownerMember?.displayName || ownerMember?.email || 'Eigentümer';
 
             return (
               <div className="flex items-center gap-1.5">
@@ -551,7 +553,7 @@ export const SharedListsView: React.FC<SharedListsViewProps> = ({ onRefreshGloba
                       title="Teilen & Berechtigungen öffnen"
                     >
                       <Users className="w-2.5 h-2.5" />
-                      <span>Geteilt von {activeSpace.ownerName || 'Eigentümer'}</span>
+                      <span>Geteilt von {ownerDisplayName}</span>
                     </button>
                   )
                 )}

frontend/src/features/triage/TasksView.tsx

@@ -948,11 +948,14 @@ export const TasksView: React.FC<TasksViewProps> = ({
         {/* Right Header Section: Sharing Badge, Icon-Only Button & View Switcher */}
         <div className="flex items-center gap-2">
           {currentSelectedList && (() => {
-            const isOwner = !currentSelectedList.ownerId || currentSelectedList.ownerId === currentUser?.id;
+            const listOwnerId = currentSelectedList.ownerId || currentSelectedList.userId;
+            const isOwner = currentSelectedList.isOwner !== false && (!listOwnerId || listOwnerId === currentUser?.id);
             const sharesCount = (currentSelectedList.shares?.length || 0) > 0
               ? currentSelectedList.shares.length
-              : (currentSelectedList.members?.filter((m) => m.userId !== currentSelectedList.ownerId).length || 0);
+              : (currentSelectedList.members?.filter((m) => m.userId !== listOwnerId).length || 0);
             const isShared = sharesCount > 0 || Boolean(currentSelectedList.teamId) || ((currentSelectedList.members?.length || 0) > 1);
+            const ownerMember = currentSelectedList.members?.find((m) => m.role === 'owner' || m.userId === listOwnerId);
+            const ownerDisplayName = currentSelectedList.ownerName || ownerMember?.displayName || ownerMember?.email || 'Eigentümer';
 
             return (
               <div className="flex items-center gap-1.5">
@@ -975,7 +978,7 @@ export const TasksView: React.FC<TasksViewProps> = ({
                       title="Teilen & Berechtigungen öffnen"
                     >
                       <Users className="w-2.5 h-2.5" />
-                      <span>Geteilt von {currentSelectedList.ownerName || 'Eigentümer'}</span>
+                      <span>Geteilt von {ownerDisplayName}</span>
                     </button>
                   )
                 )}

frontend/src/features/workspace/WorkspaceView.tsx

@@ -4512,7 +4512,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
                   ) : (
                     <div className="space-y-1.5 max-h-56 overflow-y-auto">
                       {docShares.map((share) => {
-                        const isTeam = share.targetType === 'team' || Boolean(share.teamId) || String(share.targetId || '').startsWith('team_');
+                        const isTeam = share.targetType === 'team' || Boolean((share as any).teamId) || String(share.targetId || '').startsWith('team_');
                         const targetKey = share.targetId || share.userId || share.id;
                         return (
                           <div

frontend/src/lib/api.ts

@@ -13,6 +13,7 @@ import {
   SharedList,
   Space,
   SpaceMember,
+  SpaceShare,
   SystemSettings,
   Team,
   TaskList,

frontend/src/lib/types.ts

@@ -95,6 +95,7 @@ export interface TaskList {
   spaceName?: string;
   teamId?: string;
   teamName?: string;
+  ownerId?: string;
   ownerName?: string;
   isOwner?: boolean;
   members?: TaskListMember[];
@@ -165,6 +166,7 @@ export interface DocShare {
   targetType?: 'user' | 'team';
   targetId?: string;
   targetName?: string;
+  teamId?: string;
   userId?: string;
   userEmail?: string;
   displayName?: string;
@@ -260,6 +262,7 @@ export interface Space {
   inviteCode: string;
   isPersonal: boolean;
   ownerId: string;
+  ownerName?: string;
   members?: SpaceMember[];
   shares?: SpaceShare[];
   listsCount: number;