diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheel.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheel.kt
index b5f5ba8..ec41230 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheel.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheel.kt
@@ -10,11 +10,11 @@ class ColorWheel(
 
     private val log: Logger = LoggerFactory.getLogger(javaClass)
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         return toHtml(configHolder, false)
     }
 
-    fun toHtml(configHolder: ConfigHolder, oddEven: Boolean): String {
+    fun toHtml(configHolder: ConfigHolder?, oddEven: Boolean): String {
         val wheelId = id!!.replace(" ", "")
 
         val sb = StringBuilder()
@@ -50,17 +50,17 @@ class ColorWheel(
         sb.append("\t\t</div><!-- colorwheel-panel -->\n")
     }
 
-    private fun renderScript(sb: StringBuilder, wheelId: String, oddEven: Boolean, configHolder: ConfigHolder) {
+    private fun renderScript(sb: StringBuilder, wheelId: String, oddEven: Boolean, configHolder: ConfigHolder?) {
         if (oddEven) {
             sb.append("\t\t<script type=\"application/javascript\">\n")
 
-            val hexColorOdd = configHolder.getColor("${wheelId}Odd")?:"000000"
+            val hexColorOdd = configHolder?.getColor("${wheelId}Odd")?:"000000"
             sb.append("\t\t\tvar colorWheel${wheelId}Odd = new iro.ColorPicker(\"#colorwheel-${wheelId}Odd\", {\n")
             sb.append("\t\t\t\twheelLightness: false,\n")
             sb.append("\t\t\t\tcolor: \"${hexColorOdd}\"\n")
             sb.append("\t\t\t});\n\n")
 
-            val hexColorEven = configHolder.getColor("${wheelId}Even")?:"000000"
+            val hexColorEven = configHolder?.getColor("${wheelId}Even")?:"000000"
             sb.append("\t\t\tvar colorWheel${wheelId}Even = new iro.ColorPicker(\"#colorwheel-${wheelId}Even\", {\n")
             sb.append("\t\t\t\twheelLightness: false,\n")
             sb.append("\t\t\t\tcolor: \"${hexColorEven}\"\n")
@@ -80,9 +80,9 @@ class ColorWheel(
 
             sb.append("\t\t</script>\n")
         } else {
-            val hexColor = configHolder.getFadeable(wheelId)
+            val hexColor = configHolder?.getFadeable(wheelId)
                 ?.getRgbColor()?.web()
-                ?:configHolder.getColor(wheelId)
+                ?:configHolder?.getColor(wheelId)
                 ?:"000000"
             sb.append("\t\t<script type=\"application/javascript\">\n")
 
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheelOddEven.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheelOddEven.kt
index 65e4f1d..432737a 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheelOddEven.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/ColorWheelOddEven.kt
@@ -7,7 +7,7 @@ class ColorWheelOddEven(
     val id: String? = null
 ) : HtmlRenderable {
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         return "    <div class=\"colorwheel-wrapper\">\n" +
                 "\t\t<div class=\"colorwheel-title\"><span class=\"label\">COLORPICKER</span></div>\n" +
                 "\t\t<div class=\"colorwheel-panel\">\n" +
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/HtmlRenderable.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/HtmlRenderable.kt
index 440fd5c..6d0aefe 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/HtmlRenderable.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/HtmlRenderable.kt
@@ -3,7 +3,9 @@ package de.visualdigits.kotlin.klanglicht.rest.lightmanager.model.html
 import de.visualdigits.kotlin.klanglicht.rest.configuration.ConfigHolder
 
 interface HtmlRenderable {
-    fun toHtml(configHolder: ConfigHolder): String?
+
+    fun toHtml(configHolder: ConfigHolder? = null): String?
+
     fun renderLabel(sb: StringBuilder, label: String?) {
         sb.append("<span class=\"label\">").append(label).append("</span>\n")
     }
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlActor.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlActor.kt
index d4cef26..6608773 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlActor.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlActor.kt
@@ -13,7 +13,7 @@ class LMHtmlActor(
     val actor: LMActor
 ) : HtmlRenderable {
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         val sb = StringBuilder()
         sb.append("      <div class=\"panel\">\n")
         renderLabel(sb, actor.name)
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScene.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScene.kt
index 9691683..f18012e 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScene.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScene.kt
@@ -8,13 +8,13 @@ class LMHtmlScene(
     val scene: LMScene
 ) : HtmlRenderable {
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         return toHtml(configHolder, "")
     }
 
-    fun toHtml(configHolder: ConfigHolder, group: String): String {
+    fun toHtml(configHolder: ConfigHolder?, group: String): String {
 //        val url = configHolder.preferences?.getService("lmair")?.url
-        val url = configHolder.preferences?.ownUrl
+        val url = configHolder?.preferences?.ownUrl
         val sb = StringBuilder()
         sb.append("      <div class=\"button\"")
         if (scene.color.isNotEmpty()) {
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScenes.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScenes.kt
index ad5c783..a13dd37 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScenes.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlScenes.kt
@@ -8,7 +8,7 @@ class LMHtmlScenes(
     val scene: LMScenes
 ) : HtmlRenderable {
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         val sb = StringBuilder()
         sb.append("<div class=\"title\" onclick=\"toggleFullScreen();\" title=\"Toggle Fullscreen\">")
             .append(scene.name)
@@ -16,7 +16,7 @@ class LMHtmlScenes(
         sb.append("<div class=\"center-category\">\n")
         renderLabel(sb, "C U R R E N T   S C E N E")
         sb.append("<div class=\"center-group\">\n")
-        configHolder.currentScene?.fadeables()?.forEach { fadeable ->
+        configHolder?.currentScene?.fadeables()?.forEach { fadeable ->
             val color = fadeable.getRgbColor()?.web()?:"#000000"
             val html = renderPanel("circle", color, "")
             sb.append(html)
@@ -49,7 +49,7 @@ class LMHtmlScenes(
     }
 
     private fun renderScenesGroup(
-        configHolder: ConfigHolder,
+        configHolder: ConfigHolder?,
         sceneGroup: LMSceneGroup
     ): String {
         val sb = StringBuilder()
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZone.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZone.kt
index 31242a5..0891b50 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZone.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZone.kt
@@ -7,7 +7,7 @@ class LMHtmlZone(
     val zone: LMZone
 ): HtmlRenderable {
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         val sb = StringBuilder()
         sb.append("  <div class=\"group\">\n")
         renderLabel(sb, zone.name)
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZones.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZones.kt
index 3e0fbbf..70885b3 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZones.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/lightmanager/model/html/LMHtmlZones.kt
@@ -7,7 +7,7 @@ class LMHtmlZones(
     val zones: LMZones
 ) : HtmlRenderable {
 
-    override fun toHtml(configHolder: ConfigHolder): String {
+    override fun toHtml(configHolder: ConfigHolder?): String {
         val sb = StringBuilder()
         sb.append("<div class=\"title\" onclick=\"toggleFullScreen();\" title=\"Toggle Fullscreen\">")
             .append(zones.name)
diff --git a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/shelly/model/html/ShellyStatus.kt b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/shelly/model/html/ShellyStatus.kt
index cd1323c..c4ea4fd 100644
--- a/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/shelly/model/html/ShellyStatus.kt
+++ b/klanglicht-rest/src/main/kotlin/de/visualdigits/kotlin/klanglicht/rest/shelly/model/html/ShellyStatus.kt
@@ -75,7 +75,7 @@ class ShellyStatus : HtmlRenderable {
         sb.append("      </div> <!-- ").append(clazz).append(" -->\n")
     }
 
-    override fun toHtml(configHolder: ConfigHolder): String? {
+    override fun toHtml(configHolder: ConfigHolder?): String? {
         return null
     }
 }