Bug 122045 Template should show blank preview when there is no image
Create a template but do not associate an image with it. Place the template in the templates directory. Now, create a new report design. On the second page of the New Report dialog, select the template that has no image. Actual result: The preview appears as a white rectangle with a small red square in the top left. Expected result: The preview appears as a gray background in the preview image area.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/wizards/WizardTemplateChoicePage.java
previewPane.setLayoutData( data );
		gridLayout = new GridLayout( );
		gridLayout.verticalSpacing = 10;
		previewPane.setLayout( gridLayout );
		previewCanvas = new ImageCanvas( previewPane, SWT.BORDER );
		data = new GridData( GridData.BEGINNING );
		data.heightHint = 229;
		data.widthHint = 184;
		previewCanvas.setLayoutData( data );
		Label descriptionTitle = new Label( previewPane, SWT.NONE );
		descriptionTitle.setText( MESSAGE_DESCRIPTION );
		data = new GridData( GridData.FILL_HORIZONTAL );
		descriptionTitle.setLayoutData( data );
		description = new Label( previewPane, SWT.WRAP );
		data = new GridData( GridData.FILL_HORIZONTAL );
		data.widthHint = 184;
		data.horizontalIndent = 20;
		description.setLayoutData( data );
		new Label( previewPane, SWT.NONE );
		chkBox = new Button( composite, SWT.CHECK );
		chkBox.setText( MESSAGE_SHOW_CHEATSHEET );
		chkBox.setSelection( ReportPlugin.readCheatSheetPreference( ) );
		chkBox.addSelectionListener( new SelectionListener( ) {
			public void widgetSelected( SelectionEvent e )
			{
				ReportPlugin.writeCheatSheetPreference( chkBox.getSelection( ) );
			}
			public void widgetDefaultSelected( SelectionEvent e )
			{
				ReportPlugin.writeCheatSheetPreference( chkBox.getSelection( ) );