Bug 153387 Database item can't be dragged and dropped onto editor field
Steps to reproduce: 1.Start up BIRT in Mac OS X; 2.File->New->Project; 3.File->New->Report Design; 4.In Data Explorer, create a New Data Source, and choose "Classic Models Inc. Sample DataBase", press "Next" and then press "finish"; 5.In Data Explorer, create a New Data Set, press "Next"; 6.In the popup window, expand the "CLASSICMODELS", select and drag a item onto the editor field at right side.
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
{
						availableDbObjectsTree.setRedraw( false );
						availableDbObjectsTree.deselectAll( );
						availableDbObjectsTree.setRedraw( true );
						availableDbObjectsTree.redraw( );
					}
				}
			}
		} );
		
		
		Group selectTableGroup = new Group( tablescomposite, SWT.FILL );
		{
			GridLayout groupLayout = new GridLayout( );
			groupLayout.numColumns = 3;
			
			groupLayout.verticalSpacing = 10;
			selectTableGroup.setLayout( groupLayout );
			GridData data = new GridData( GridData.FILL_HORIZONTAL );
			selectTableGroup.setLayoutData( data );
		}
		schemaLabel = new Label( selectTableGroup, SWT.LEFT );
		schemaLabel.setText( JdbcPlugin.getResourceString( "tablepage.label.schema" ) );
		schemaCombo = new Combo( selectTableGroup, SWT.READ_ONLY );
		GridData gd = new GridData( GridData.FILL_HORIZONTAL );
		gd.horizontalSpan = 2;
		schemaCombo.setLayoutData( gd );
		enableSchemaComponent( isSchemaSupported );
		Label FilterLabel = new Label( selectTableGroup, SWT.LEFT );
		FilterLabel.setText( JdbcPlugin.getResourceString( "tablepage.label.filter" ) );