diff --git a/CHANGELOG.md b/CHANGELOG.md
index 171a3d4b..92db04e9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,4 @@
+- Fixed occasional ConcurrentModificationException when the screen-poll timer reads the terminal buffer concurrently with PTY writes
 - Fixed tab title showing "Claude Code" for sessions opened in non-project directories — now shows the directory name
 - Added OpenAI-compatible proxy: profiles can now route Claude Code through any OpenAI-compatible API provider (OpenAI, Azure, Groq, DeepSeek, Ollama, local models, etc.)
 
diff --git a/pom.xml b/pom.xml
index aebe314a..e31a8c64 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>io.github.nbplugins</groupId>
     <artifactId>netbeans-plugin-claude-code-gui</artifactId>
-    <version>1.2.9-SNAPSHOT</version>
+    <version>1.2.10-SNAPSHOT</version>
     <packaging>nbm</packaging>
     <name>Netbeans Plugin Claude Code GUI</name>
     <description>NetBeans plugin that provides a GUI for Claude Code CLI — run claude code sessions directly inside the IDE.</description>
diff --git a/src/main/java/io/github/nbplugins/claudecodegui/ui/ClaudeSessionTab.java b/src/main/java/io/github/nbplugins/claudecodegui/ui/ClaudeSessionTab.java
index 7ee18931..10bb86ab 100644
--- a/src/main/java/io/github/nbplugins/claudecodegui/ui/ClaudeSessionTab.java
+++ b/src/main/java/io/github/nbplugins/claudecodegui/ui/ClaudeSessionTab.java
@@ -1470,13 +1470,17 @@ private void walkScrollComponents(java.awt.Container c, StringBuilder sb, int de
 
     private List<String> getScreenLines() {
         if (terminalWidget == null) return java.util.Collections.emptyList();
+        TerminalTextBuffer buf = terminalWidget.getTerminalTextBuffer();
+        if (buf == null) return java.util.Collections.emptyList();
+        if (!buf.tryLock()) return java.util.Collections.emptyList();
         try {
-            TerminalTextBuffer buf = terminalWidget.getTerminalTextBuffer();
             return buf.getScreenBuffer().getLineTexts();
         } catch (NullPointerException e) {
             // JediTerm's LinesStorage may return null entries during terminal
             // initialization. Return empty so pollScreenState retries next tick.
             return java.util.Collections.emptyList();
+        } finally {
+            buf.unlock();
         }
     }