diff --git a/CHANGELOG.md b/CHANGELOG.md
index b0063e5c..14f6ed73 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 
 ### Fixed
 - MutableMetaImpl attachment and checks
+- Listeners in observable meta are replaced by lists
 
 ### Security
 ## [0.5.0]
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableMeta.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableMeta.kt
index f2b80417..8fa432cc 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableMeta.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/ObservableMeta.kt
@@ -48,7 +48,7 @@ public interface ObservableMutableMeta : ObservableMeta, MutableMeta, MutableTyp
 }
 
 internal abstract class AbstractObservableMeta : ObservableMeta {
-    private val listeners = ArrayList<MetaListener>()
+    private val listeners: MutableList<MetaListener> = mutableListOf()
 
     override fun invalidate(name: Name) {
         listeners.forEach { it.callback(this, name) }
diff --git a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt
index d4f40eb4..2bc0e234 100644
--- a/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt
+++ b/dataforge-meta/src/commonMain/kotlin/space/kscience/dataforge/meta/Scheme.kt
@@ -1,6 +1,9 @@
 package space.kscience.dataforge.meta
 
-import space.kscience.dataforge.meta.descriptors.*
+import space.kscience.dataforge.meta.descriptors.Described
+import space.kscience.dataforge.meta.descriptors.MetaDescriptor
+import space.kscience.dataforge.meta.descriptors.get
+import space.kscience.dataforge.meta.descriptors.validate
 import space.kscience.dataforge.misc.DFExperimental
 import space.kscience.dataforge.names.*
 import space.kscience.dataforge.values.Value
@@ -64,7 +67,7 @@ public open class Scheme : Described, MetaRepr, MutableMetaProvider, Configurabl
 
     override fun toMeta(): Laminate = Laminate(meta, descriptor?.defaultNode)
 
-    private val listeners = HashSet<MetaListener>()
+    private val listeners: MutableList<MetaListener> = mutableListOf()
 
     private inner class SchemeMeta(val pathName: Name) : ObservableMutableMeta {
         override var value: Value?