diff --git a/core/src/main/java/de/srsoftware/umbrella/core/model/Task.java b/core/src/main/java/de/srsoftware/umbrella/core/model/Task.java
index 046972e..4b9c4f2 100644
--- a/core/src/main/java/de/srsoftware/umbrella/core/model/Task.java
+++ b/core/src/main/java/de/srsoftware/umbrella/core/model/Task.java
@@ -164,7 +164,10 @@ public class Task implements Mappable {
 				case NAME:           name          = json.getString(key); break;
 				case NO_INDEX:       noIndex       = json.getBoolean(NO_INDEX); break;
 				case PARENT_TASK_ID: parentTaskId  = json.getLong(PARENT_TASK_ID); break;
-				case REQUIRED_TASKS_IDS: requiredTasksIds.addAll(json.getJSONArray(REQUIRED_TASKS_IDS).toList().stream().map(entry -> Long.parseLong(entry.toString())).toList()); break;
+				case REQUIRED_TASKS_IDS:
+					requiredTasksIds.clear();
+					requiredTasksIds.addAll(json.getJSONArray(REQUIRED_TASKS_IDS).toList().stream().map(entry -> Long.parseLong(entry.toString())).toList());
+					break;
 				case SHOW_CLOSED:    showClosed    = json.getBoolean(SHOW_CLOSED); break;
 				case START_DATE:     start         = json.isNull(START_DATE) || json.getString(START_DATE).isBlank() ? null : LocalDate.parse(json.getString(START_DATE)); break;
 				case STATUS:         status        = json.getInt(key); break;
diff --git a/frontend/src/routes/task/RequiredTasks.svelte b/frontend/src/routes/task/RequiredTasks.svelte
index 24b8b4d..3ad719d 100644
--- a/frontend/src/routes/task/RequiredTasks.svelte
+++ b/frontend/src/routes/task/RequiredTasks.svelte
@@ -22,20 +22,14 @@
             error = null;
             let newTask = await resp.json();
             if (newTask.project_id != task.project_id){
-                alert('prject mismatch!');
+                alert('project mismatch!');
                 return;
             }
             task.required_tasks_ids.push(new_task_id);
             requiredTasks[new_task_id] = newTask;
-            url = api(`task/${task.id}`);
-            resp = await fetch(url,{
-                credentials : 'include',
-                method      : 'PATCH',
-                body        : JSON.stringify({required_tasks_ids:task.required_tasks_ids})
-            });
+            await patch();
             delete candidates[new_task_id];
-        }
-        if (!resp.ok) {
+        } else {
             error = await resp.text();
         }
     }
@@ -90,6 +84,24 @@
         return false;
     }
 
+    async function patch(){
+            const url  = api(`task/${task.id}`);
+            const resp = await fetch(url,{
+                credentials : 'include',
+                method      : 'PATCH',
+                body        : JSON.stringify({required_tasks_ids:task.required_tasks_ids})
+            });
+            if (!resp.ok){
+                error = await resp.text();
+            }
+    }
+
+    async function unlink(required_task){
+        task.required_tasks_ids = task.required_tasks_ids.filter(item => item != required_task.id);
+        patch();
+        delete requiredTasks[required_task.id];
+    }
+
     onMount(loadTasks);
 </script>
 
@@ -97,7 +109,7 @@
 <ul class="required task list">
     {#each Object.values(requiredTasks) as task}
     <li class="task" >
-        <a href="/task/{task.id}/view" onclick={openTask} >{task.name}</a>
+        <a href="/task/{task.id}/view" onclick={openTask} >{task.name}</a>&nbsp;<button onclick={() => unlink(task)} class="symbol"></button>
     </li>
     {/each}
 </ul>
diff --git a/task/src/main/java/de/srsoftware/umbrella/task/SqliteDb.java b/task/src/main/java/de/srsoftware/umbrella/task/SqliteDb.java
index 1a47e97..99b4b7e 100644
--- a/task/src/main/java/de/srsoftware/umbrella/task/SqliteDb.java
+++ b/task/src/main/java/de/srsoftware/umbrella/task/SqliteDb.java
@@ -316,9 +316,19 @@ CREATE TABLE IF NOT EXISTS {0} (
 				task.clean(MEMBERS);
 			}
 			if (task.isDirty(REQUIRED_TASKS_IDS)) {
-				var query = replaceInto(TABLE_TASK_DEPENDENCIES,TASK_ID,REQUIRED_TASK_ID);
-				for (var reqId : task.requiredTasksIds()) query.values(task.id(),reqId);
-				query.execute(db).close();
+				var dropQuery = Query.delete().from(TABLE_TASK_DEPENDENCIES).where(TASK_ID,equal(task.id()));
+				if (!task.requiredTasksIds().isEmpty()){
+					dropQuery.where(REQUIRED_TASK_ID,notIn(task.requiredTasksIds().toArray()));
+					db.setAutoCommit(false);
+				}
+				dropQuery.execute(db);
+				if (!task.requiredTasksIds().isEmpty()) {
+					var addQuery = replaceInto(TABLE_TASK_DEPENDENCIES, TASK_ID, REQUIRED_TASK_ID);
+					for (var reqId : task.requiredTasksIds()) addQuery.values(task.id(), reqId);
+					addQuery.execute(db).close();
+					db.setAutoCommit(true);
+				}
+
 				task.clean(REQUIRED_TASKS_IDS);
 			}
 			if (task.isDirty()) {