Bug 291755 [Filters] Filters implementation and API cleanup
This bug is raised to track reviewing and cleanup of filters API and implementation.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/dialogs/ResourceFilterGroup.java
* @param parentShell
	 * @param filter
	 */
	public FilterEditDialog(Shell parentShell, FilterCopy filter) {
		super(parentShell);
		this.filter = filter;
		util = new FilterTypeUtil();
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jface.dialogs.Dialog#createDialogArea(org.eclipse.swt.widgets
	 * .Composite)
	 */
	protected Control createDialogArea(Composite parent) {
		GridData data = new GridData(SWT.FILL, SWT.FILL, true, true);
		parent.setLayoutData(data);
		Font font = parent.getFont();
		Composite composite = new Composite(parent, SWT.NONE);
		GridLayout layout = new GridLayout();
		layout.numColumns = 1;
		layout.marginHeight = convertVerticalDLUsToPixels(IDialogConstants.VERTICAL_MARGIN);
		layout.marginWidth = convertHorizontalDLUsToPixels(IDialogConstants.HORIZONTAL_MARGIN);
		layout.verticalSpacing = convertVerticalDLUsToPixels(IDialogConstants.VERTICAL_SPACING);
		layout.horizontalSpacing = convertHorizontalDLUsToPixels(IDialogConstants.HORIZONTAL_SPACING);
		composite.setLayout(layout);
		data = new GridData(SWT.FILL, SWT.FILL, true, true);
		composite.setLayoutData(data);
		composite.setFont(font);