diff --git a/cave/com.raytheon.uf.viz.derivparam.ui/src/com/raytheon/uf/viz/derivparam/ui/actions/NewDerivedParameterAction.java b/cave/com.raytheon.uf.viz.derivparam.ui/src/com/raytheon/uf/viz/derivparam/ui/actions/NewDerivedParameterAction.java
index ccaf452309..22a1b35503 100644
--- a/cave/com.raytheon.uf.viz.derivparam.ui/src/com/raytheon/uf/viz/derivparam/ui/actions/NewDerivedParameterAction.java
+++ b/cave/com.raytheon.uf.viz.derivparam.ui/src/com/raytheon/uf/viz/derivparam/ui/actions/NewDerivedParameterAction.java
@@ -36,6 +36,7 @@ import com.raytheon.viz.ui.dialogs.CaveSWTWizardDlg;
  * Date         Ticket#    Engineer    Description
  * ------------ ---------- ----------- --------------------------
  * Dec 14, 2010            mschenke     Initial creation
+ * Oct 22, 2012 1229       rferrel     Changes for non-blocking CaveSWTWizardDlg.
  * 
  * </pre>
  * 
@@ -44,6 +45,7 @@ import com.raytheon.viz.ui.dialogs.CaveSWTWizardDlg;
  */
 
 public class NewDerivedParameterAction extends Action {
+    private CaveSWTWizardDlg dialog;
 
     /**
      * 
@@ -55,9 +57,13 @@ public class NewDerivedParameterAction extends Action {
     @Override
     public void run() {
         DerivedParamWizard wizard = new DerivedParamWizard();
-        CaveSWTWizardDlg dialog = new CaveSWTWizardDlg(VizWorkbenchManager
-                .getInstance().getCurrentWindow().getShell(), wizard);
-        dialog.open();
+        if (dialog == null || dialog.getShell() == null || dialog.isDisposed()) {
+            dialog = new CaveSWTWizardDlg(VizWorkbenchManager.getInstance()
+                    .getCurrentWindow().getShell(), wizard);
+            dialog.open();
+        } else {
+            dialog.bringToTop();
+        }
     }
 
 }
diff --git a/cave/com.raytheon.viz.ui/src/com/raytheon/viz/ui/dialogs/CaveSWTWizardDlg.java b/cave/com.raytheon.viz.ui/src/com/raytheon/viz/ui/dialogs/CaveSWTWizardDlg.java
index 790c557d9a..2001961a46 100644
--- a/cave/com.raytheon.viz.ui/src/com/raytheon/viz/ui/dialogs/CaveSWTWizardDlg.java
+++ b/cave/com.raytheon.viz.ui/src/com/raytheon/viz/ui/dialogs/CaveSWTWizardDlg.java
@@ -46,6 +46,7 @@ import org.eclipse.swt.widgets.Shell;
  * Date         Ticket#    Engineer    Description
  * ------------ ---------- ----------- --------------------------
  * Dec 19, 2010            lvenable     Initial creation
+ * Oct 22, 2012 1229       rferrel     Dialog changed to non-blocking.
  * 
  * </pre>
  * 
@@ -75,7 +76,7 @@ public class CaveSWTWizardDlg extends CaveSWTDialog {
     private ArrayList<Composite> pageCompArray;
 
     public CaveSWTWizardDlg(Shell parent, CaveSWTWizard swtWizzard) {
-        super(parent, SWT.APPLICATION_MODAL | SWT.MIN);
+        super(parent, SWT.APPLICATION_MODAL | SWT.MIN, CAVE.DO_NOT_BLOCK);
         this.swtWizzard = swtWizzard;
         if (swtWizzard.getTitle() != null) {
             setText(swtWizzard.getTitle());