diff --git a/client/src/org/compiere/apps/APanel.java b/client/src/org/compiere/apps/APanel.java
index 4a157a250e..ec6ac62c54 100644
--- a/client/src/org/compiere/apps/APanel.java
+++ b/client/src/org/compiere/apps/APanel.java
@@ -2021,7 +2021,8 @@ public final class APanel extends CPanel
 		ProcessModalDialog dialog = new ProcessModalDialog(m_ctx, Env.getWindow(m_curWindowNo), Env.getHeader(m_ctx, m_curWindowNo),
 				this, m_curWindowNo, vButton.getProcess_ID(), table_ID, 
 				record_ID, startWOasking);
-		AEnv.showCenterWindow(Env.getWindow(m_curWindowNo), dialog);
+		if (dialog.isValid())
+			AEnv.showCenterWindow(Env.getWindow(m_curWindowNo), dialog);
 	}	//	actionButton
 
 	
diff --git a/client/src/org/compiere/apps/ProcessModalDialog.java b/client/src/org/compiere/apps/ProcessModalDialog.java
index dcd6597097..c18f71937a 100644
--- a/client/src/org/compiere/apps/ProcessModalDialog.java
+++ b/client/src/org/compiere/apps/ProcessModalDialog.java
@@ -87,6 +87,7 @@ public class ProcessModalDialog extends CDialog
 	private String		    m_Name = null;
 	private StringBuffer	m_messageText = new StringBuffer();
 	private String          m_ShowHelp = null; // Determine if a Help Process Window is shown
+	private boolean m_valid = true;
 	
 	/**	Logger			*/
 	private static CLogger log = CLogger.getCLogger(ProcessDialog.class);
@@ -176,9 +177,14 @@ public class ProcessModalDialog extends CDialog
 	 */
 	public void dispose()
 	{
+		m_valid = false;
 		super.dispose();
 	}	//	dispose
 
+	public boolean isValid()
+	{
+		return m_valid;
+	}
 
 	/**
 	 *	Dynamic Init