diff --git a/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/AbstractSpringIndexElement.java b/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/AbstractSpringIndexElement.java
index 7e1f90bf6..6bf5faf5a 100644
--- a/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/AbstractSpringIndexElement.java
+++ b/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/AbstractSpringIndexElement.java
@@ -11,6 +11,7 @@
 package org.springframework.ide.vscode.commons.protocol.spring;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 public abstract class AbstractSpringIndexElement implements SpringIndexElement {
@@ -24,7 +25,7 @@ public abstract class AbstractSpringIndexElement implements SpringIndexElement {
 
 	@Override
 	public List<SpringIndexElement> getChildren() {
-		return children;
+		return Collections.unmodifiableList(this.children);
 	}
 	
 	public void addChild(SpringIndexElement child) {
diff --git a/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElement.java b/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElement.java
index 0f4a26879..03bdbeb0c 100644
--- a/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElement.java
+++ b/headless-services/commons/commons-lsp-extensions/src/main/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElement.java
@@ -10,15 +10,22 @@
  *******************************************************************************/
 package org.springframework.ide.vscode.commons.protocol.spring;
 
-import java.util.Iterator;
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
-public class ProjectElement extends AbstractSpringIndexElement {
+public class ProjectElement implements SpringIndexElement {
 
 	private String projectName;
+	
+	private Map<String, DocumentElement> documents;
+	private List<SpringIndexElement> otherElements;
 
 	public ProjectElement(String projectName) {
 		this.projectName = projectName;
+		this.documents = new ConcurrentHashMap<>();
+		this.otherElements = new ArrayList<>();
 	}
 	
 	public String getProjectName() {
@@ -26,13 +33,36 @@ public class ProjectElement extends AbstractSpringIndexElement {
 	}
 
 	public void removeDocument(String docURI) {
-		List<SpringIndexElement> children = this.getChildren();
+		this.documents.remove(docURI);
+	}
+
+	@Override
+	public List<SpringIndexElement> getChildren() {
+		List<SpringIndexElement> result = new ArrayList<>();
+
+		result.addAll(documents.values());
+		result.addAll(otherElements);
 		
-		for (Iterator<SpringIndexElement> iterator = children.iterator(); iterator.hasNext();) {
-			SpringIndexElement springIndexElement = (SpringIndexElement) iterator.next();
-			if (springIndexElement instanceof DocumentElement doc && doc.getDocURI().equals(docURI)) {
-				iterator.remove();
-			}
+		return result;
+	}
+
+	@Override
+	public void addChild(SpringIndexElement child) {
+		if (child instanceof DocumentElement document) {
+			documents.put(document.getDocURI(), document);
+		}
+		else {
+			otherElements.add(child);
+		}
+	}
+
+	@Override
+	public void removeChild(SpringIndexElement doc) {
+		if (doc instanceof DocumentElement document) {
+			documents.remove(document.getDocURI());
+		}
+		else {
+			otherElements.remove(doc);
 		}
 	}
 
diff --git a/headless-services/commons/commons-lsp-extensions/src/test/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElementTest.java b/headless-services/commons/commons-lsp-extensions/src/test/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElementTest.java
new file mode 100644
index 000000000..e763ec6a7
--- /dev/null
+++ b/headless-services/commons/commons-lsp-extensions/src/test/java/org/springframework/ide/vscode/commons/protocol/spring/ProjectElementTest.java
@@ -0,0 +1,129 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Broadcom
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Broadcom - initial API and implementation
+ *******************************************************************************/
+package org.springframework.ide.vscode.commons.protocol.spring;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+class ProjectElementTest {
+
+	@Test
+	void testAddDocumentChildren() {
+		ProjectElement project = new ProjectElement("projectName");
+		
+		List<SpringIndexElement> children = project.getChildren();
+		assertEquals(0, children.size());
+		
+		DocumentElement doc1 = new DocumentElement("docUri1");
+		DocumentElement doc2 = new DocumentElement("docUri2");
+		
+		project.addChild(doc1);
+		project.addChild(doc2);
+		
+		children = project.getChildren();
+		assertEquals(2, children.size());
+		
+		assertTrue(children.contains(doc1));
+		assertTrue(children.contains(doc2));
+	}
+
+	@Test
+	void testAddNonDocumentChildren() {
+		ProjectElement project = new ProjectElement("projectName");
+		
+		var child1 = new AbstractSpringIndexElement() {};
+		var child2 = new AbstractSpringIndexElement() {};
+		
+		project.addChild(child1);
+		project.addChild(child2);
+		
+		List<SpringIndexElement> children = project.getChildren();
+		assertEquals(2, children.size());
+		
+		assertTrue(children.contains(child1));
+		assertTrue(children.contains(child2));
+	}
+
+	@Test
+	void testMixedProjectChildren() {
+		ProjectElement project = new ProjectElement("projectName");
+		
+		var doc1 = new DocumentElement("docUri1");
+		var doc2 = new DocumentElement("docUri2");
+		
+		project.addChild(doc1);
+		project.addChild(doc2);
+		
+		var child1 = new AbstractSpringIndexElement() {};
+		var child2 = new AbstractSpringIndexElement() {};
+		
+		project.addChild(child1);
+		project.addChild(child2);
+		
+		List<SpringIndexElement> children = project.getChildren();
+		assertEquals(4, children.size());
+		
+		assertTrue(children.contains(child1));
+		assertTrue(children.contains(child2));
+		assertTrue(children.contains(doc1));
+		assertTrue(children.contains(doc2));
+	}
+	
+	@Test
+	void testRemoveProjectChildren() {
+		ProjectElement project = new ProjectElement("projectName");
+		
+		var doc1 = new DocumentElement("docUri1");
+		var doc2 = new DocumentElement("docUri2");
+		
+		project.addChild(doc1);
+		project.addChild(doc2);
+		
+		var child1 = new AbstractSpringIndexElement() {};
+		var child2 = new AbstractSpringIndexElement() {};
+		
+		project.addChild(child1);
+		project.addChild(child2);
+		
+		project.removeDocument("docUri1");
+		List<SpringIndexElement> children = project.getChildren();
+		assertEquals(3, children.size());
+		
+		assertTrue(children.contains(child1));
+		assertTrue(children.contains(child2));
+		assertFalse(children.contains(doc1));
+		assertTrue(children.contains(doc2));
+		
+		project.removeDocument("docDoesNotExist");
+		children = project.getChildren();
+		assertEquals(3, children.size());
+		
+		assertTrue(children.contains(child1));
+		assertTrue(children.contains(child2));
+		assertFalse(children.contains(doc1));
+		assertTrue(children.contains(doc2));
+
+		project.removeChild(child2);
+		children = project.getChildren();
+		assertEquals(2, children.size());
+		
+		assertTrue(children.contains(child1));
+		assertFalse(children.contains(child2));
+		assertFalse(children.contains(doc1));
+		assertTrue(children.contains(doc2));
+	}
+	
+}