diff --git a/web/client-api/src/main/java/io/deephaven/web/client/api/tree/JsTreeTable.java b/web/client-api/src/main/java/io/deephaven/web/client/api/tree/JsTreeTable.java
index 7163ae034d9..72e7ea11116 100644
--- a/web/client-api/src/main/java/io/deephaven/web/client/api/tree/JsTreeTable.java
+++ b/web/client-api/src/main/java/io/deephaven/web/client/api/tree/JsTreeTable.java
@@ -599,7 +599,8 @@ private void replaceSubscription(RebuildStep step) {
                     viewTicket.release();
                     viewTicket = null;
                 }
-            case SUBSCRIPTION:
+
+                // In all of the above cases, we replace the subscription
                 if (stream != null) {
                     stream.then(stream -> {
                         stream.close();
@@ -607,6 +608,16 @@ private void replaceSubscription(RebuildStep step) {
                     });
                     stream = null;
                 }
+                break;
+            case SUBSCRIPTION:
+                // If it exists, adjust the existing subscription, otherwise create a new one
+                if (stream != null) {
+                    stream.then(subscription -> {
+                        subscription.setViewport(firstRow, lastRow, Js.uncheckedCast(columns), (double) updateInterval);
+                        return null;
+                    });
+                    return;
+                }
         }
 
         Promise<TreeSubscription> stream = Promise.resolve(defer())
diff --git a/web/client-api/src/test/java/io/deephaven/web/client/api/HierarchicalTableTestGwt.java b/web/client-api/src/test/java/io/deephaven/web/client/api/HierarchicalTableTestGwt.java
index 54ace6db598..191b8d73f72 100644
--- a/web/client-api/src/test/java/io/deephaven/web/client/api/HierarchicalTableTestGwt.java
+++ b/web/client-api/src/test/java/io/deephaven/web/client/api/HierarchicalTableTestGwt.java
@@ -50,6 +50,16 @@ public void testStaticTreeTable() {
                                         JsTreeTable.EVENT_UPDATED, 2001d);
                             }).then(event -> {
                                 assertEquals(10d, event.detail.getTreeSize());
+                                assertEquals(10, event.detail.getRows().length);
+
+
+                                // move the viewport and try again
+                                treeTable.setViewport(5, 50, treeTable.getColumns(), null);
+                                return treeTable.<TreeViewportData>nextEvent(
+                                        JsTreeTable.EVENT_UPDATED, 2002d);
+                            }).then(event -> {
+                                assertEquals(10d, event.detail.getTreeSize());
+                                assertEquals(5, event.detail.getRows().length);
 
                                 treeTable.close();
 
@@ -133,6 +143,15 @@ public void testRefreshingTreeTable() {
                                 assertEquals(green, data.getFormat(1, idCol));
                                 assertEquals(green, row2.getFormat(idCol));
                                 assertEquals(green, idCol.getFormat(row2));
+
+                                // Move the viewport and make sure we get the correct data
+                                treeTable.setViewport(5, 49, treeTable.getColumns(), null);
+                                return treeTable.<TreeViewportData>nextEvent(
+                                        JsTreeTable.EVENT_UPDATED, 2002d);
+                            }).then(event -> {
+                                assertEquals(10d, event.detail.getTreeSize());
+                                assertEquals(5, event.detail.getRows().length);
+
                                 return Promise.resolve(treeTable);
                             })
                             .then(event -> {