diff --git a/renderdocui/Windows/Dialogs/PythonShell.Designer.cs b/renderdocui/Windows/Dialogs/PythonShell.Designer.cs
index 58316ef83..9a194504f 100644
--- a/renderdocui/Windows/Dialogs/PythonShell.Designer.cs
+++ b/renderdocui/Windows/Dialogs/PythonShell.Designer.cs
@@ -28,6 +28,7 @@
         /// </summary>
         private void InitializeComponent()
         {
+            this.components = new System.ComponentModel.Container();
             System.Windows.Forms.ToolStripContainer toolStripContainer1;
             System.Windows.Forms.ToolStrip toolStrip1;
             System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(PythonShell));
@@ -50,6 +51,7 @@
             this.saveDialog = new System.Windows.Forms.SaveFileDialog();
             this.openDialog = new System.Windows.Forms.OpenFileDialog();
             this.newScript = new System.Windows.Forms.ToolStripButton();
+            this.linenumTimer = new System.Windows.Forms.Timer(this.components);
             toolStripContainer1 = new System.Windows.Forms.ToolStripContainer();
             toolStrip1 = new System.Windows.Forms.ToolStrip();
             toolStripContainer1.ContentPanel.SuspendLayout();
@@ -301,6 +303,11 @@
             this.newScript.Text = "New";
             this.newScript.Click += new System.EventHandler(this.newScript_Click);
             // 
+            // linenumTimer
+            // 
+            this.linenumTimer.Interval = 500;
+            this.linenumTimer.Tick += new System.EventHandler(this.linenumTimer_Tick);
+            // 
             // PythonShell
             // 
             this.AllowDrop = true;
@@ -356,6 +363,7 @@
         private System.Windows.Forms.SaveFileDialog saveDialog;
         private System.Windows.Forms.OpenFileDialog openDialog;
         private System.Windows.Forms.ToolStripButton newScript;
+        private System.Windows.Forms.Timer linenumTimer;
 
 
     }
diff --git a/renderdocui/Windows/Dialogs/PythonShell.cs b/renderdocui/Windows/Dialogs/PythonShell.cs
index ecdfa15d0..8db9a5aec 100644
--- a/renderdocui/Windows/Dialogs/PythonShell.cs
+++ b/renderdocui/Windows/Dialogs/PythonShell.cs
@@ -287,9 +287,9 @@ namespace renderdocui.Windows.Dialogs
         {
             if (result == "exception")
             {
-            System.Diagnostics.Trace.WriteLine("On line " + frame.f_lineno.ToString());
-                linenum = (int)frame.f_lineno - 1;
+                System.Diagnostics.Trace.WriteLine("On line " + frame.f_lineno.ToString());
             }
+            linenum = (int)frame.f_lineno - 1;
 
             stdoutwriter.Flush();
             stdout.Seek(0, SeekOrigin.Begin);
@@ -339,6 +339,9 @@ namespace renderdocui.Windows.Dialogs
 
             EnableButtons(false);
 
+            linenumTimer.Enabled = true;
+            linenumTimer.Start();
+
             Thread th = Helpers.NewThread(new ThreadStart(() =>
             {
                 pythonengine.SetTrace(PythonTrace);
@@ -346,6 +349,7 @@ namespace renderdocui.Windows.Dialogs
                 // ignore output, the trace handler above will print output
                 string output = Execute(pythonengine, scriptscope, script);
 
+                linenumTimer.Stop();
                 pythonengine.SetTrace(null);
 
                 this.BeginInvoke(new Action(() =>
@@ -439,5 +443,10 @@ namespace renderdocui.Windows.Dialogs
 
             scriptEditor.Text = scriptEditor.Text.Replace("\n", Environment.NewLine);
         }
+
+        private void linenumTimer_Tick(object sender, EventArgs e)
+        {
+            SetLineNumber(linenum);
+        }
     }
 }
diff --git a/renderdocui/Windows/Dialogs/PythonShell.resx b/renderdocui/Windows/Dialogs/PythonShell.resx
index f58f6b829..398af4c95 100644
--- a/renderdocui/Windows/Dialogs/PythonShell.resx
+++ b/renderdocui/Windows/Dialogs/PythonShell.resx
@@ -166,4 +166,7 @@
   <metadata name="openDialog.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
     <value>318, 16</value>
   </metadata>
+  <metadata name="linenumTimer.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+    <value>433, 16</value>
+  </metadata>
 </root>
\ No newline at end of file