diff --git a/quickstep/src/com/android/quickstep/util/DeviceConfigHelper.kt b/quickstep/src/com/android/quickstep/util/DeviceConfigHelper.kt
index d36dc7e..2dd727e 100644
--- a/quickstep/src/com/android/quickstep/util/DeviceConfigHelper.kt
+++ b/quickstep/src/com/android/quickstep/util/DeviceConfigHelper.kt
@@ -26,19 +26,21 @@
 import androidx.annotation.WorkerThread
 import com.android.launcher3.BuildConfig
 import com.android.launcher3.util.Executors
+import java.util.concurrent.CopyOnWriteArrayList
 
 /** Utility class to manage a set of device configurations */
 class DeviceConfigHelper<ConfigType>(private val factory: (PropReader) -> ConfigType) {
 
     var config: ConfigType
         private set
+
     private val allKeys: Set<String>
     private val propertiesListener = OnPropertiesChangedListener { onDevicePropsChanges(it) }
     private val sharedPrefChangeListener = OnSharedPreferenceChangeListener { _, _ ->
         recreateConfig()
     }
 
-    private val changeListeners = mutableListOf<Runnable>()
+    private val changeListeners = CopyOnWriteArrayList<Runnable>()
 
     init {
         // Initialize the default config once.