diff --git a/silk-plugins/silk-plugins-csv/src/main/scala/org/silkframework/plugins/dataset/csv/CsvDatasetTrait.scala b/silk-plugins/silk-plugins-csv/src/main/scala/org/silkframework/plugins/dataset/csv/CsvDatasetTrait.scala
index a1cbfd6b6a..6b86fd6d8b 100644
--- a/silk-plugins/silk-plugins-csv/src/main/scala/org/silkframework/plugins/dataset/csv/CsvDatasetTrait.scala
+++ b/silk-plugins/silk-plugins-csv/src/main/scala/org/silkframework/plugins/dataset/csv/CsvDatasetTrait.scala
@@ -32,6 +32,7 @@ trait CsvDatasetTrait {
   val separatorChar: Char =
     if (separator == "\\t") { '\t' }
     else if (separator.length == 1) { separator.head }
+    else if(separator.isEmpty) { ',' }
     else { throw new IllegalArgumentException(s"Invalid separator: '$separator'. Must be a single character.") }
 
   val arraySeparatorChar: Option[Char] =
diff --git a/silk-react-components/src/HierarchicalMapping/elements/RuleTitle.jsx b/silk-react-components/src/HierarchicalMapping/elements/RuleTitle.jsx
index 7d3aa8ce39..8ca8d42dd7 100644
--- a/silk-react-components/src/HierarchicalMapping/elements/RuleTitle.jsx
+++ b/silk-react-components/src/HierarchicalMapping/elements/RuleTitle.jsx
@@ -4,7 +4,8 @@ import { NotAvailable } from '@eccenca/gui-elements';
 import { ThingName } from '../components/ThingName';
 
 import {
-    MAPPING_RULE_TYPE_ROOT,
+    MAPPING_RULE_TYPE_COMPLEX_URI,
+    MAPPING_RULE_TYPE_ROOT, MAPPING_RULE_TYPE_URI,
 } from '../utils/constants';
 import { MAPPING_RULE_TYPE_COMPLEX, MAPPING_RULE_TYPE_DIRECT, MAPPING_RULE_TYPE_OBJECT } from '../utils/constants';
 
@@ -35,7 +36,12 @@ const RuleTitle = ({ rule, ...otherProps }) => {
         ) : (
             <NotAvailable />
         );
+    case MAPPING_RULE_TYPE_URI:
+    case MAPPING_RULE_TYPE_COMPLEX_URI:
+        return <span>uri</span>
     }
+
+    return <NotAvailable />;
 };
 
 export default RuleTitle;
diff --git a/silk-workbench/silk-workbench-workspace/app/controllers/workspaceApi/search/ItemTypeFacetCollector.scala b/silk-workbench/silk-workbench-workspace/app/controllers/workspaceApi/search/ItemTypeFacetCollector.scala
index 5782f8b18f..a77127e7f0 100644
--- a/silk-workbench/silk-workbench-workspace/app/controllers/workspaceApi/search/ItemTypeFacetCollector.scala
+++ b/silk-workbench/silk-workbench-workspace/app/controllers/workspaceApi/search/ItemTypeFacetCollector.scala
@@ -8,6 +8,8 @@ import org.silkframework.rule.{LinkSpec, TransformSpec}
 import org.silkframework.workspace.activity.workflow.Workflow
 import org.silkframework.workspace.{Project, ProjectTask}
 
+import java.util.concurrent.ConcurrentHashMap
+import java.util.logging.Logger
 import scala.collection.immutable.ListMap
 import scala.collection.mutable
 import scala.reflect.ClassTag
@@ -42,6 +44,9 @@ trait ItemTypeFacetCollector[T  <: TaskSpec] {
 }
 
 object ItemTypeFacetCollector {
+  private val logger: Logger = Logger.getLogger(this.getClass.getName)
+  private val facetErrorsLogged = new ConcurrentHashMap[String, Long]()
+
   /** Returns true if the project task should be in the result set according to the facet setting.
     * It collects facet values after filtering.
     * Values are collected for each facet, when no other facet filters out a project task. */
@@ -64,7 +69,14 @@ object ItemTypeFacetCollector {
             matchingFacets.add(facetSetting.facetId)
           }
         case None =>
-          throw new IllegalArgumentException(s"Facet ID '${facetSetting.facetId}' is not available for facet collector '${this.getClass.getSimpleName}'.")
+          // Unknown facet always matches
+          matchingFacets.add(facetSetting.facetId)
+          val facetKey = this.getClass.getSimpleName + "_" + facetSetting.facetId
+          if(Option(facetErrorsLogged.get(facetKey)).isEmpty || facetErrorsLogged.get(facetKey) < (System.currentTimeMillis() - 1000)) {
+            logger.warning(s"Wrong facet configuration in search request. Facet ID '${facetSetting.facetId}' is " +
+              s"not available for facet collector '${this.getClass.getSimpleName}'.")
+            facetErrorsLogged.put(facetKey, System.currentTimeMillis())
+          }
       }
     }
     val allMatch = facetSettings.size == matchingFacets.size // Only when all requested facet settings match, it's an overall match
diff --git a/silk-workspace/src/main/scala/org/silkframework/workspace/PluginBasedWorkspaceFactory.scala b/silk-workspace/src/main/scala/org/silkframework/workspace/PluginBasedWorkspaceFactory.scala
index 66d039412d..2f78138826 100644
--- a/silk-workspace/src/main/scala/org/silkframework/workspace/PluginBasedWorkspaceFactory.scala
+++ b/silk-workspace/src/main/scala/org/silkframework/workspace/PluginBasedWorkspaceFactory.scala
@@ -14,14 +14,15 @@
 
 package org.silkframework.workspace
 
-import java.util.logging.{Level, Logger}
-
-import javax.inject.Inject
 import org.silkframework.config.{Config, DefaultConfig}
 import org.silkframework.runtime.activity.UserContext
 import org.silkframework.runtime.plugin.PluginRegistry
 import org.silkframework.workspace.resources.ResourceRepository
 
+import java.time.Instant
+import java.util.logging.{Level, Logger}
+import javax.inject.Inject
+
 class PluginBasedWorkspaceFactory extends WorkspaceFactory {
 
   override def workspace(implicit userContext: UserContext): Workspace = PluginBasedWorkspaceFactory.workspace
@@ -29,16 +30,25 @@ class PluginBasedWorkspaceFactory extends WorkspaceFactory {
 }
 
 object PluginBasedWorkspaceFactory {
+
   private val log: Logger = Logger.getLogger(this.getClass.getName.stripSuffix("$"))
+
   @Inject
   private var configMgr: Config = DefaultConfig.instance
 
+  @volatile
+  private var timestamp: Instant = Instant.MIN
+
   private var _workspace: Option[Workspace] = None
 
   def workspace(implicit userContext: UserContext): Workspace = this.synchronized {
     _workspace match {
-      case Some(w) => w
-      case None =>
+      case Some(w) if !timestamp.isBefore(configMgr.timestamp) => w
+      case _ =>
+        if(_workspace.nonEmpty) {
+          log.info("Reloading workspace because the configuration has been updated.")
+        }
+        timestamp = configMgr.timestamp
         try {
           val w = initWorkspace
           _workspace = Some(w)