diff --git a/Ghidra/Debug/Debugger-gadp/src/test/java/ghidra/dbg/gadp/GadpClientServerTest.java b/Ghidra/Debug/Debugger-gadp/src/test/java/ghidra/dbg/gadp/GadpClientServerTest.java
index 7438992dba..283fb2211f 100644
--- a/Ghidra/Debug/Debugger-gadp/src/test/java/ghidra/dbg/gadp/GadpClientServerTest.java
+++ b/Ghidra/Debug/Debugger-gadp/src/test/java/ghidra/dbg/gadp/GadpClientServerTest.java
@@ -984,6 +984,8 @@ public class GadpClientServerTest implements AsyncTestUtils {
 		AsynchronousSocketChannel socket = socketChannel();
 		try (ServerRunner runner = new ServerRunner()) {
 			GadpClient client = new GadpClient("Test", socket);
+			client.addModelListener(focusListener);
+
 			waitOn(AsyncUtils.completable(TypeSpec.VOID, socket::connect,
 				runner.server.getLocalAddress()));
 			waitOn(client.connect());
@@ -1044,7 +1046,7 @@ public class GadpClientServerTest implements AsyncTestUtils {
 		AsynchronousSocketChannel socket = socketChannel();
 		try (ServerRunner runner = new ServerRunner()) {
 			GadpClient client = new GadpClient("Test", socket);
-
+			client.addModelListener(elemL);
 			waitOn(AsyncUtils.completable(TypeSpec.VOID, socket::connect,
 				runner.server.getLocalAddress()));
 			waitOn(client.connect());
diff --git a/Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/service/model/DebuggerModelServicePlugin.java b/Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/service/model/DebuggerModelServicePlugin.java
index bd550915e4..94d0e740b0 100644
--- a/Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/service/model/DebuggerModelServicePlugin.java
+++ b/Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/service/model/DebuggerModelServicePlugin.java
@@ -240,7 +240,7 @@ public class DebuggerModelServicePlugin extends Plugin
 	public boolean addModel(DebuggerObjectModel model) {
 		Objects.requireNonNull(model);
 		synchronized (models) {
-			if (models.contains(model)) {
+			if (!models.add(model)) {
 				return false;
 			}
 			model.addModelListener(forRemovalAndFocusListener);