diff --git a/dbux-data/src/callGraph/CallGraph.js b/dbux-data/src/callGraph/CallGraph.js
index a231a587e..cad671aa6 100644
--- a/dbux-data/src/callGraph/CallGraph.js
+++ b/dbux-data/src/callGraph/CallGraph.js
@@ -262,16 +262,14 @@ export default class CallGraph {
     const trace = this.dp.collections.traces.getById(traceId);
     const realContextId = this.dp.util.getRealContextIdOfTrace(traceId);
     const parentTraces = this.dp.indexes.traces.parentsByRealContext.get(realContextId) || EmptyArray;
-    const callerTraces = parentTraces.map(t => this.dp.util.getPreviousCallerTraceOfTrace(t.traceId))
-      .sort((t1, t2) => t1.traceId - t2.traceId);
 
-    const lowerIndex = this._binarySearchLowerIndexByKey(callerTraces, trace, (t) => t.traceId);
+    const lowerIndex = this._binarySearchLowerIndexByKey(parentTraces, trace, (t) => t.traceId);
 
     if (lowerIndex === null) {
       return null;
     }
     else {
-      return this.dp.util.getBCETraceOfTrace(callerTraces[lowerIndex].traceId);
+      return this.dp.util.getBCETraceOfTrace(parentTraces[lowerIndex].traceId);
     }
   }
 
@@ -279,16 +277,14 @@ export default class CallGraph {
     const realContextId = this.dp.util.getRealContextIdOfTrace(traceId);
     const trace = this.dp.collections.traces.getById(traceId);
     const parentTraces = this.dp.indexes.traces.parentsByRealContext.get(realContextId) || EmptyArray;
-    const callerTraces = parentTraces.map(t => this.dp.util.getPreviousCallerTraceOfTrace(t.traceId))
-      .sort((t1, t2) => t1.traceId - t2.traceId);
 
-    const upperIndex = this._binarySearchUpperIndexByKey(callerTraces, trace, (t) => t.traceId);
+    const upperIndex = this._binarySearchUpperIndexByKey(parentTraces, trace, (t) => t.traceId);
 
     if (upperIndex === null) {
       return null;
     }
     else {
-      return this.dp.util.getBCETraceOfTrace(callerTraces[upperIndex].traceId);
+      return this.dp.util.getBCETraceOfTrace(parentTraces[upperIndex].traceId);
     }
   }
 
diff --git a/dbux-data/src/impl/indexes/ParentTracesInRealContextIndex.js b/dbux-data/src/impl/indexes/ParentTracesInRealContextIndex.js
index 84790a3d6..fffe1a006 100644
--- a/dbux-data/src/impl/indexes/ParentTracesInRealContextIndex.js
+++ b/dbux-data/src/impl/indexes/ParentTracesInRealContextIndex.js
@@ -1,5 +1,5 @@
 import ExecutionContext from '@dbux/common/src/types/ExecutionContext';
-import { isVirtualContextType } from '@dbux/common/src/types/constants/ExecutionContextType';
+import ExecutionContextType from '@dbux/common/src/types/constants/ExecutionContextType';
 import Trace from '@dbux/common/src/types/Trace';
 import CollectionIndex, { CollectionIndexDependencies } from '../../indexes/CollectionIndex';
 import RuntimeDataProvider from '../../RuntimeDataProvider';
@@ -38,10 +38,14 @@ export default class ParentTracesInRealContextIndex extends CollectionIndex {
         added: (contexts) => {
           for (const context of contexts) {
             const { parentTraceId, contextId } = context;
-            // skip empty contexts
+            // skip empty contexts, e.g. `Await`s
             if (this.dp.indexes.traces.byContext.getSize(contextId) === 0) {
               continue;
             }
+
+            /**
+             * NOTE: this will filter out non-first virtual contexts, since they have no `parentTraceId`
+             */
             if (parentTraceId && !this.addedTraces.has(parentTraceId)) {
               this.addEntryById(parentTraceId);
               this.addedTraces.add(parentTraceId);