diff --git a/numass-viewer/build.gradle b/numass-viewer/build.gradle
index 511ae1c6..5cf26bbd 100644
--- a/numass-viewer/build.gradle
+++ b/numass-viewer/build.gradle
@@ -20,8 +20,12 @@ dependencies {
     compile 'com.jcraft:jsch:0.1.54'
 
     compile "org.jetbrains.kotlin:kotlin-stdlib:1.1.1"
-    //compile "org.jetbrains.kotlin:kotlin-reflect:1.1.1"
+
     compile "no.tornado:tornadofx:1.7.1"
+    // https://mvnrepository.com/artifact/org.controlsfx/controlsfx
+    compile group: 'org.controlsfx', name: 'controlsfx', version: '8.40.12'
+
+
 }
 
 //shadowJar {
diff --git a/numass-viewer/src/main/kotlin/inr/numass/viewer/NumassLoaderView.kt b/numass-viewer/src/main/kotlin/inr/numass/viewer/NumassLoaderView.kt
index bac2d3d3..d0e5f60e 100644
--- a/numass-viewer/src/main/kotlin/inr/numass/viewer/NumassLoaderView.kt
+++ b/numass-viewer/src/main/kotlin/inr/numass/viewer/NumassLoaderView.kt
@@ -50,6 +50,7 @@ class NumassLoaderView : View() {
     lateinit var main: MainView
 
     var data: NumassData? = null
+    val spectrumData = PlottableData("spectrum")
 
     private val detectorPlotPane: AnchorPane by fxid();
     private val tabPane: TabPane by fxid();
@@ -175,7 +176,6 @@ class NumassLoaderView : View() {
         getWorkManager().startWork("viewer.numass.hv") { callback: Work ->
             val t = hvData.get()
             Platform.runLater {
-//                hvPlot.plot.clear()
                 val set = PlottableGroup<TimePlottable>()
                 for (dp in t) {
                     val block = dp.getString("block", "default")
@@ -216,7 +216,6 @@ class NumassLoaderView : View() {
     }
 
     private fun setupSpectrumPane(points: List<NumassPoint>) {
-        val spectrumData = PlottableData("spectrum")
         spectrumPlot.plot.add(spectrumData)
 
         val lowChannel = channelSlider.lowValue.toInt()