diff --git a/app/src/main/java/chess/view/DDDrender/Window.java b/app/src/main/java/chess/view/DDDrender/Window.java
index edd18a4..ea3cbd2 100644
--- a/app/src/main/java/chess/view/DDDrender/Window.java
+++ b/app/src/main/java/chess/view/DDDrender/Window.java
@@ -72,11 +72,11 @@ public class Window implements Closeable {
 		this.regularTasks = new ArrayList<>();
 	}
 
-	public void addRegularTask(Consumer<Float> task) {
+	public synchronized void addRegularTask(Consumer<Float> task) {
 		this.regularTasks.add(task);
 	}
 
-	public void removeRegularTask(Consumer<Float> task) {this.regularTasks.remove(task);}
+	public synchronized void removeRegularTask(Consumer<Float> task) {this.regularTasks.remove(task);}
 
 	public synchronized void scheduleTask(Runnable runnable) {
 		this.tasks.add(runnable);
@@ -195,7 +195,7 @@ public class Window implements Closeable {
 		}
 	}
 
-	private void executeTasks(float delta) {
+	private synchronized void executeTasks(float delta) {
 		Runnable task = getNextTask();
 		while (task != null) {
 			task.run();