Fix Three color change problem

dataforge-vis-common/src/commonMain/kotlin/hep/dataforge/vis/common/AbstractVisualObject.kt

@@ -48,10 +48,12 @@ abstract class AbstractVisualObject : VisualObject {
     private val listeners = HashSet<PropertyListener>()
 
     override fun propertyChanged(name: Name, before: MetaItem<*>?, after: MetaItem<*>?) {
+        if (before != after) {
             for (l in listeners) {
                 l.action(name, before, after)
             }
         }
+    }
 
     override fun onPropertyChange(owner: Any?, action: (Name, before: MetaItem<*>?, after: MetaItem<*>?) -> Unit) {
         listeners.add(PropertyListener(owner, action))

dataforge-vis-spatial/src/jsMain/kotlin/hep/dataforge/vis/spatial/three/ThreeMaterials.kt

@@ -93,7 +93,7 @@ fun MetaItem<*>.color(): Color {
 
 fun Mesh.updateMaterial(obj: VisualObject) {
     val meta = obj.getProperty(Material3D.MATERIAL_KEY).node?:EmptyMeta
-    material = (material as? MeshBasicMaterial ?: MeshBasicMaterial()).apply {
+    material = MeshBasicMaterial().apply {
         color = meta[Material3D.COLOR_KEY]?.color() ?: ThreeMaterials.DEFAULT_COLOR
         opacity = meta[Material3D.OPACITY_KEY]?.double ?: 1.0
         transparent = opacity < 1.0

demo/gdml/build.gradle.kts

@@ -15,7 +15,7 @@ kotlin {
     js {
         browser {
             webpackTask {
-                sourceMaps = false
+                //sourceMaps = false
             }
         }
     }