diff --git a/src/compose.cpp b/src/compose.cpp
index c07607c..1dceb46 100644
--- a/src/compose.cpp
+++ b/src/compose.cpp
@@ -336,6 +336,25 @@ void composeParent(ComposeState& state, const NodeTree& tree,
             }
         }
 
+        // Embedded struct with refId but no child nodes: expand referenced struct's
+        // children at this node's offset (single instance, like array with count=1)
+        if (node.kind == NodeKind::Struct && children.isEmpty() && node.refId != 0) {
+            int refIdx = tree.indexOfId(node.refId);
+            if (refIdx >= 0) {
+                QVector<int> refChildren = state.childMap.value(node.refId);
+                std::sort(refChildren.begin(), refChildren.end(), [&](int a, int b) {
+                    return tree.nodes[a].offset < tree.nodes[b].offset;
+                });
+                for (int childIdx : refChildren) {
+                    // Skip self-referential children (e.g. struct Ball has a field of type Ball)
+                    if (state.visiting.contains(tree.nodes[childIdx].id))
+                        continue;
+                    composeNode(state, tree, prov, childIdx, childDepth,
+                                absAddr, node.refId, false, node.id);
+                }
+            }
+        }
+
         // For arrays, render children as condensed (no header/footer for struct elements)
         bool childrenAreArrayElements = (node.kind == NodeKind::Array);
         int elementIdx = 0;
diff --git a/src/controller.cpp b/src/controller.cpp
index a9c0e85..4a1c63c 100644
--- a/src/controller.cpp
+++ b/src/controller.cpp
@@ -1703,6 +1703,63 @@ void RcxController::applyTypePopupResult(TypePopupMode mode, int nodeIdx,
         if (entry.entryKind == TypeEntry::Primitive) {
             if (entry.primitiveKind != node.kind)
                 changeNodeKind(nodeIdx, entry.primitiveKind);
+        } else if (entry.entryKind == TypeEntry::Composite) {
+            bool wasSuppressed = m_suppressRefresh;
+            m_suppressRefresh = true;
+            m_doc->undoStack.beginMacro(QStringLiteral("Change to composite type"));
+
+            if (spec.isPointer) {
+                // Pointer modifier: e.g. "Material*" → Pointer64 + refId
+                if (node.kind != NodeKind::Pointer64)
+                    changeNodeKind(nodeIdx, NodeKind::Pointer64);
+                int idx = m_doc->tree.indexOfId(node.id);
+                if (idx >= 0 && m_doc->tree.nodes[idx].refId != entry.structId)
+                    m_doc->undoStack.push(new RcxCommand(this,
+                        cmd::ChangePointerRef{node.id, m_doc->tree.nodes[idx].refId, entry.structId}));
+
+            } else if (spec.arrayCount > 0) {
+                // Array modifier: e.g. "Material[10]" → Array + Struct element
+                if (node.kind != NodeKind::Array)
+                    changeNodeKind(nodeIdx, NodeKind::Array);
+                int idx = m_doc->tree.indexOfId(node.id);
+                if (idx >= 0) {
+                    auto& n = m_doc->tree.nodes[idx];
+                    if (n.elementKind != NodeKind::Struct || n.arrayLen != spec.arrayCount)
+                        m_doc->undoStack.push(new RcxCommand(this,
+                            cmd::ChangeArrayMeta{node.id, n.elementKind, NodeKind::Struct,
+                                                 n.arrayLen, spec.arrayCount}));
+                    if (n.refId != entry.structId)
+                        m_doc->undoStack.push(new RcxCommand(this,
+                            cmd::ChangePointerRef{node.id, n.refId, entry.structId}));
+                }
+
+            } else {
+                // Plain struct: e.g. "Material" → Struct + structTypeName + refId + collapsed
+                if (node.kind != NodeKind::Struct)
+                    changeNodeKind(nodeIdx, NodeKind::Struct);
+                int idx = m_doc->tree.indexOfId(node.id);
+                if (idx >= 0) {
+                    int refIdx = m_doc->tree.indexOfId(entry.structId);
+                    QString targetName;
+                    if (refIdx >= 0) {
+                        const Node& ref = m_doc->tree.nodes[refIdx];
+                        targetName = ref.structTypeName.isEmpty() ? ref.name : ref.structTypeName;
+                    }
+                    QString oldTypeName = m_doc->tree.nodes[idx].structTypeName;
+                    if (oldTypeName != targetName)
+                        m_doc->undoStack.push(new RcxCommand(this,
+                            cmd::ChangeStructTypeName{node.id, oldTypeName, targetName}));
+                    // Set refId so compose can expand the referenced struct's children
+                    if (m_doc->tree.nodes[idx].refId != entry.structId)
+                        m_doc->undoStack.push(new RcxCommand(this,
+                            cmd::ChangePointerRef{node.id, m_doc->tree.nodes[idx].refId, entry.structId}));
+                    // ChangePointerRef auto-sets collapsed=true when refId != 0
+                }
+            }
+
+            m_doc->undoStack.endMacro();
+            m_suppressRefresh = wasSuppressed;
+            if (!m_suppressRefresh) refresh();
         }
     } else if (mode == TypePopupMode::ArrayElement) {
         if (entry.entryKind == TypeEntry::Primitive) {
diff --git a/src/core.h b/src/core.h
index 294eca6..26e61a7 100644
--- a/src/core.h
+++ b/src/core.h
@@ -366,6 +366,10 @@ struct NodeTree {
             if (end > maxEnd) maxEnd = end;
         }
 
+        // Embedded struct reference: no own children but refId points to a struct definition
+        if (kids.isEmpty() && node.kind == NodeKind::Struct && node.refId != 0)
+            maxEnd = qMax(maxEnd, structSpan(node.refId, childMap, visited));
+
         return qMax(declaredSize, maxEnd);
     }
 
diff --git a/tests/test_type_selector.cpp b/tests/test_type_selector.cpp
index 338e278..954b89a 100644
--- a/tests/test_type_selector.cpp
+++ b/tests/test_type_selector.cpp
@@ -405,6 +405,186 @@ private slots:
         QCOMPARE(spec.arrayCount, 0);
     }
 
+    // ── FieldType popup: selecting a composite (struct) type changes node kind + structTypeName + collapsed ──
+
+    void testFieldTypeCompositeChangesNodeToStruct() {
+        auto* doc = new RcxDocument();
+        buildTwoRootTree(doc->tree);
+        doc->provider = std::make_unique<BufferProvider>(makeBuffer());
+
+        auto* splitter = new QSplitter();
+        auto* ctrl = new RcxController(doc, nullptr);
+        ctrl->addSplitEditor(splitter);
+
+        splitter->resize(800, 600);
+        splitter->show();
+        QVERIFY(QTest::qWaitForWindowExposed(splitter));
+        ctrl->refresh();
+        QApplication::processEvents();
+
+        // Find the "x" field (Int32) inside Alpha struct, and Bravo struct id
+        int xIdx = -1;
+        uint64_t bravoId = 0;
+        for (int i = 0; i < doc->tree.nodes.size(); i++) {
+            const auto& n = doc->tree.nodes[i];
+            if (n.name == "x" && n.kind == NodeKind::Int32) xIdx = i;
+            if (n.name == "Bravo" && n.kind == NodeKind::Struct) bravoId = n.id;
+        }
+        QVERIFY(xIdx >= 0);
+        QVERIFY(bravoId != 0);
+
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Int32);
+        QVERIFY(!doc->tree.nodes[xIdx].collapsed);
+        uint64_t xNodeId = doc->tree.nodes[xIdx].id;
+
+        // Simulate the plain-struct path of applyTypePopupResult:
+        // beginMacro → changeNodeKind(Struct) → ChangeStructTypeName → ChangePointerRef → endMacro
+        doc->undoStack.beginMacro(QStringLiteral("Change to composite type"));
+        ctrl->changeNodeKind(xIdx, NodeKind::Struct);
+
+        xIdx = doc->tree.indexOfId(xNodeId);
+        QVERIFY(xIdx >= 0);
+
+        int bravoIdx = doc->tree.indexOfId(bravoId);
+        QVERIFY(bravoIdx >= 0);
+        QString targetName = doc->tree.nodes[bravoIdx].structTypeName;
+
+        doc->undoStack.push(new RcxCommand(ctrl,
+            cmd::ChangeStructTypeName{xNodeId, doc->tree.nodes[xIdx].structTypeName, targetName}));
+
+        // Set refId so compose can expand referenced struct children (auto-collapses)
+        doc->undoStack.push(new RcxCommand(ctrl,
+            cmd::ChangePointerRef{xNodeId, 0, bravoId}));
+
+        doc->undoStack.endMacro();
+        QApplication::processEvents();
+
+        // Verify: Struct with correct name, refId, AND collapsed
+        xIdx = doc->tree.indexOfId(xNodeId);
+        QVERIFY(xIdx >= 0);
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Struct);
+        QCOMPARE(doc->tree.nodes[xIdx].structTypeName, QString("Bravo"));
+        QCOMPARE(doc->tree.nodes[xIdx].refId, bravoId);
+        QVERIFY(doc->tree.nodes[xIdx].collapsed);
+
+        // Single undo reverses the entire macro
+        doc->undoStack.undo();
+        QApplication::processEvents();
+        xIdx = doc->tree.indexOfId(xNodeId);
+        QVERIFY(xIdx >= 0);
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Int32);
+        QCOMPARE(doc->tree.nodes[xIdx].refId, uint64_t(0));
+        QVERIFY(doc->tree.nodes[xIdx].structTypeName.isEmpty());
+
+        delete ctrl;
+        delete splitter;
+        delete doc;
+    }
+
+    // ── FieldType popup: selecting a composite with * modifier creates Pointer64 + refId ──
+
+    void testFieldTypeCompositeWithPointerModifier() {
+        auto* doc = new RcxDocument();
+        buildTwoRootTree(doc->tree);
+        doc->provider = std::make_unique<BufferProvider>(makeBuffer());
+
+        auto* splitter = new QSplitter();
+        auto* ctrl = new RcxController(doc, nullptr);
+        ctrl->addSplitEditor(splitter);
+
+        splitter->resize(800, 600);
+        splitter->show();
+        QVERIFY(QTest::qWaitForWindowExposed(splitter));
+        ctrl->refresh();
+        QApplication::processEvents();
+
+        // Find the "x" field (Int32) and Bravo struct
+        int xIdx = -1;
+        uint64_t bravoId = 0;
+        for (int i = 0; i < doc->tree.nodes.size(); i++) {
+            const auto& n = doc->tree.nodes[i];
+            if (n.name == "x" && n.kind == NodeKind::Int32) xIdx = i;
+            if (n.name == "Bravo" && n.kind == NodeKind::Struct) bravoId = n.id;
+        }
+        QVERIFY(xIdx >= 0);
+        QVERIFY(bravoId != 0);
+
+        uint64_t xNodeId = doc->tree.nodes[xIdx].id;
+
+        // Simulate the pointer path of applyTypePopupResult:
+        // beginMacro → changeNodeKind(Pointer64) → ChangePointerRef → endMacro
+        doc->undoStack.beginMacro(QStringLiteral("Change to composite type"));
+        ctrl->changeNodeKind(xIdx, NodeKind::Pointer64);
+
+        xIdx = doc->tree.indexOfId(xNodeId);
+        QVERIFY(xIdx >= 0);
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Pointer64);
+
+        doc->undoStack.push(new RcxCommand(ctrl,
+            cmd::ChangePointerRef{xNodeId, 0, bravoId}));
+        doc->undoStack.endMacro();
+        QApplication::processEvents();
+
+        // Verify: Pointer64 with refId pointing to Bravo, auto-collapsed
+        xIdx = doc->tree.indexOfId(xNodeId);
+        QVERIFY(xIdx >= 0);
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Pointer64);
+        QCOMPARE(doc->tree.nodes[xIdx].refId, bravoId);
+        QVERIFY(doc->tree.nodes[xIdx].collapsed);
+
+        // Single undo reverses the entire macro
+        doc->undoStack.undo();
+        QApplication::processEvents();
+        xIdx = doc->tree.indexOfId(xNodeId);
+        QVERIFY(xIdx >= 0);
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Int32);
+        QCOMPARE(doc->tree.nodes[xIdx].refId, uint64_t(0));
+
+        delete ctrl;
+        delete splitter;
+        delete doc;
+    }
+
+    // ── FieldType popup: selecting a primitive type still works ──
+
+    void testFieldTypePrimitiveStillWorks() {
+        auto* doc = new RcxDocument();
+        buildTwoRootTree(doc->tree);
+        doc->provider = std::make_unique<BufferProvider>(makeBuffer());
+
+        auto* splitter = new QSplitter();
+        auto* ctrl = new RcxController(doc, nullptr);
+        ctrl->addSplitEditor(splitter);
+
+        splitter->resize(800, 600);
+        splitter->show();
+        QVERIFY(QTest::qWaitForWindowExposed(splitter));
+        ctrl->refresh();
+        QApplication::processEvents();
+
+        // Find the "x" field (Int32)
+        int xIdx = -1;
+        for (int i = 0; i < doc->tree.nodes.size(); i++) {
+            if (doc->tree.nodes[i].name == "x") { xIdx = i; break; }
+        }
+        QVERIFY(xIdx >= 0);
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Int32);
+
+        // Change to Float via changeNodeKind (same path as primitive TypeEntry)
+        ctrl->changeNodeKind(xIdx, NodeKind::Float);
+        QApplication::processEvents();
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Float);
+
+        // Undo
+        doc->undoStack.undo();
+        QApplication::processEvents();
+        QCOMPARE(doc->tree.nodes[xIdx].kind, NodeKind::Int32);
+
+        delete ctrl;
+        delete splitter;
+        delete doc;
+    }
+
     // ── Section headers in filtered list ──
 
     void testSectionHeadersPresent() {