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
schemaCombo.add( it.next( ).toString( ) );
			}
		}
		ArrayList schemaObjectList = new ArrayList( );
		if ( schemaList != null )
		{
			int numberOfSchema = 0;
			Preferences preferences = JdbcPlugin.getDefault( )
					.getPluginPreferences( );
			if ( preferences.contains( DateSetPreferencePage.USER_MAX_NUM_OF_SCHEMA ) )
			{
				numberOfSchema = preferences.getInt( DateSetPreferencePage.USER_MAX_NUM_OF_SCHEMA );
			}
			else
			{
				numberOfSchema = DateSetPreferencePage.DEFAULT_MAX_NUM_OF_SCHEMA;
				preferences.setValue( DateSetPreferencePage.USER_MAX_NUM_OF_SCHEMA,
						numberOfSchema );
			}
			cachedSchemaComboIndex = schemaCombo.getSelectionIndex( );
			if ( schemaCombo.getSelectionIndex( ) == 0 )
			{
				for ( int i = 0, count = 0; i < schemaList.size( )
						&& count < numberOfSchema; i++ )
				{
					String schemaName = (String) schemaList.get( i );
					if ( containsTableInSchema( schemaName ) )
					{
						DbObject schemaObj = new DbObject( schemaName,
								schemaName,