diff --git a/ui/kotlinx-coroutines-javafx/src/JavaFxConvert.kt b/ui/kotlinx-coroutines-javafx/src/JavaFxConvert.kt
index 10c7e7be0d..9725c03f32 100644
--- a/ui/kotlinx-coroutines-javafx/src/JavaFxConvert.kt
+++ b/ui/kotlinx-coroutines-javafx/src/JavaFxConvert.kt
@@ -1,3 +1,7 @@
+/*
+ *  Copyright 2016-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
 package kotlinx.coroutines.javafx
 
 import javafx.beans.value.ChangeListener
@@ -20,9 +24,16 @@ import kotlinx.coroutines.flow.flowOn
  *
  * Since this implementation uses [ObservableValue.addListener], even if this [ObservableValue]
  * supports lazy evaluation, eager computation will be enforced while the flow is being collected.
+ *
+ * All the calls to JavaFX API are performed in the JavaFX application thread.
+ *
+ * ### Operator fusion
+ *
+ * Adjacent applications of [flowOn], [buffer], [conflate], and [produceIn] to the result of `asFlow` are fused.
+ * [conflate] has no effect, as this flow is already conflated; one can use [buffer] to change that instead.
  */
 @ExperimentalCoroutinesApi
-public fun <T: Any> ObservableValue<T>.asFlow(): Flow<T> = callbackFlow<T> {
+public fun <T> ObservableValue<T>.asFlow(): Flow<T> = callbackFlow<T> {
     val listener = ChangeListener<T> { _, _, newValue ->
         try {
             offer(newValue)
diff --git a/ui/kotlinx-coroutines-javafx/test/JavaFxObservableAsFlowTest.kt b/ui/kotlinx-coroutines-javafx/test/JavaFxObservableAsFlowTest.kt
index a39dedb551..6964050102 100644
--- a/ui/kotlinx-coroutines-javafx/test/JavaFxObservableAsFlowTest.kt
+++ b/ui/kotlinx-coroutines-javafx/test/JavaFxObservableAsFlowTest.kt
@@ -24,7 +24,7 @@ class JavaFxObservableAsFlowTest : TestBase() {
         }
 
         val integerProperty = SimpleIntegerProperty(0)
-        val n = 10000 * stressTestMultiplier
+        val n = 1000
         val flow = integerProperty.asFlow().takeWhile { j -> j != n }
         newSingleThreadContext("setter").use { pool ->
             launch(pool) {
diff --git a/ui/kotlinx-coroutines-javafx/test/JavaFxStressTest.kt b/ui/kotlinx-coroutines-javafx/test/JavaFxStressTest.kt
index a572c0434c..fd7436214a 100644
--- a/ui/kotlinx-coroutines-javafx/test/JavaFxStressTest.kt
+++ b/ui/kotlinx-coroutines-javafx/test/JavaFxStressTest.kt
@@ -14,7 +14,7 @@ class JavaFxStressTest : TestBase() {
     }
 
     @Test
-    fun cancellationRaceStressTest() = runTest {
+    fun testCancellationRace() = runTest {
         if (!initPlatform()) {
             println("Skipping JavaFxTest in headless environment")
             return@runTest // ignore test in headless environments
diff --git a/ui/kotlinx-coroutines-javafx/test/examples/FxAsFlow.kt b/ui/kotlinx-coroutines-javafx/test/examples/FxAsFlow.kt
index bb0463bd79..3a3745c743 100644
--- a/ui/kotlinx-coroutines-javafx/test/examples/FxAsFlow.kt
+++ b/ui/kotlinx-coroutines-javafx/test/examples/FxAsFlow.kt
@@ -26,12 +26,12 @@ class FxAsFlowApp: Application(), CoroutineScope {
     override val coroutineContext: CoroutineContext
         get() = JavaFx + job
 
-    private  val  incrementBttn = Button("Increment")
-    private  val  incrementLabel = Label("")
-    private  val  textInput = TextField()
-    private  val  flippedTextLabel = Label()
-    private  val  spinner = Spinner<Int>()
-    private  val  spinnerChangesLabel = Label()
+    private val incrementBttn = Button("Increment")
+    private val incrementLabel = Label("")
+    private val textInput = TextField()
+    private val flippedTextLabel = Label()
+    private val spinner = Spinner<Int>()
+    private val spinnerChangesLabel = Label()
 
     public override fun start(  primaryStage: Stage) {
         val gridPane = GridPane()
@@ -61,7 +61,7 @@ class FxAsFlowApp: Application(), CoroutineScope {
 
     init {
         // Initializing the "Increment" button
-        val stringProperty = SimpleStringProperty("")
+        val stringProperty = SimpleStringProperty()
         var i = 0
         incrementBttn.onAction = EventHandler {
             i += 1
@@ -76,7 +76,7 @@ class FxAsFlowApp: Application(), CoroutineScope {
         }
         incrementLabel.textProperty().bind(stringProperty)
         // Initializing the reversed text field
-        val stringProperty2 = SimpleStringProperty("")
+        val stringProperty2 = SimpleStringProperty()
         launch {
             textInput.textProperty().asFlow().collect {
                 if (it != null) {
@@ -88,7 +88,7 @@ class FxAsFlowApp: Application(), CoroutineScope {
         // Initializing the spinner
         spinner.valueFactory = SpinnerValueFactory.IntegerSpinnerValueFactory(0, 100)
         spinner.isEditable = true
-        val stringProperty3 = SimpleStringProperty("")
+        val stringProperty3 = SimpleStringProperty()
         launch {
             spinner.valueProperty().asFlow().collect {
                 if (it != null) {