Fix for zkwebui - report fields - drop down field not cleared https://sourceforge.net/projects/adempiere/forums/forum/610547/topic/4450695

org.adempiere.ui.zk/WEB-INF/src/org/adempiere/webui/apps/ProcessParameterPanel.java

@@ -40,6 +40,7 @@ import org.compiere.apps.IProcessParameter;
 import org.compiere.model.GridField;
 import org.compiere.model.GridFieldVO;
 import org.compiere.model.MClient;
+import org.compiere.model.MLookup;
 import org.compiere.model.MPInstancePara;
 import org.compiere.process.ProcessInfo;
 import org.compiere.util.CLogger;
@@ -479,9 +480,54 @@ public class ProcessParameterPanel extends Panel implements
 	 */
 
 	public void valueChange(ValueChangeEvent evt) {
+		if (evt.getSource() instanceof WEditor) {
+			GridField changedField = ((WEditor) evt.getSource()).getGridField();
+			if (changedField != null) {
+				processDependencies (changedField);
+				// future processCallout (changedField);
+			}
+		}
 		processNewValue(evt.getNewValue(), evt.getPropertyName());
 	}
 
+	/**
+	 *  Evaluate Dependencies
+	 *  @param changedField changed field
+	 */
+	private void processDependencies (GridField changedField)
+	{
+		String columnName = changedField.getColumnName();
+
+		for (GridField field : m_mFields) {
+			if (field == null || field == changedField)
+				continue;
+			verifyChangedField(field, columnName);
+		}
+		for (GridField field : m_mFields2) {
+			if (field == null || field == changedField)
+				continue;
+			verifyChangedField(field, columnName);
+		}
+	}   //  processDependencies
+
+	private void verifyChangedField(GridField field, String columnName) {
+		ArrayList<String> list = field.getDependentOn();
+		if (list.contains(columnName)) {
+			if (field.getLookup() instanceof MLookup)
+			{
+				MLookup mLookup = (MLookup)field.getLookup();
+				//  if the lookup is dynamic (i.e. contains this columnName as variable)
+				if (mLookup.getValidation().indexOf("@"+columnName+"@") != -1)
+				{
+					log.fine(columnName + " changed - "
+						+ field.getColumnName() + " set to null");
+					//  invalidate current selection
+					field.setValue(null, true);
+				}
+			}
+		}
+	}
+	
 	private void processNewValue(Object value, String name) {
 		if (value == null)
 			value = new String("");