Bug 199021 Error message pops up several times when click an invalid dataset
Description: There is a sqlserver datasource and dataset, remove the jtds driver to let the dataset invalid. Double click on the dataset, the error message will pop up serveral times. Build version:2.2.0.v20070807-0630 Steps to reproduce: 1. Create a sqlserver datasource and dataset. 2. Remove the jtds driver, and the dataset will be invalid. 3. Double click on the dataset. Expect result: Error message pops up once to indicate the problem. Actual result: Error message pops up serveral times.
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
DbObject schemaObj = new DbObject( schemaName,
								schemaName,
								DbObject.SCHEMA_TYPE,
								schemaImage );
						schemaObjectList.add( schemaObj );
						count++;
					}
				}
			}
			else if ( schemaCombo.getSelectionIndex( ) > 0 )
			{
				String schemaName = schemaCombo.getItem( schemaCombo.getSelectionIndex( ) );
				DbObject schemaObj = new DbObject( schemaName,
						schemaName,
						DbObject.SCHEMA_TYPE,
						schemaImage );
				schemaObjectList.add( schemaObj );
			}
		}
		TreeItem[] items = Utility.createTreeItems( rootNode,
				schemaObjectList,
				SWT.NONE,
				schemaImage );
		if ( items != null && items.length > 0 )
		{
			availableDbObjectsTree.showItem( items[0] );
		}
		
	}