Included tab context conflict issue

Fixed the bug introducing in revision 12410, the problem is with Dynamic field into Process Dialog parameters

Teo can you check if your commit have not other collateral effects

kind regards
Victor Perez
www.e-evolution.com
Link to SF Tracker: http://sourceforge.net/support/tracker.php?aid=3007342

base/src/org/compiere/model/GridField.java

@@ -799,6 +799,9 @@ public class GridField
 	 */
 	public String get_ValueAsString (String variableName)
 	{
+	   if( m_vo.TabNo == 0)
+	    	return Env.getContext (m_vo.ctx, m_vo.WindowNo, variableName, true);
+	    else
 		return Env.getContext (m_vo.ctx, m_vo.WindowNo, m_vo.TabNo, variableName, false, true);
 	}	//	get_ValueAsString