Bug 180645 Support set format for Date/Time type parameter.[0705]
Description: Support set format for Date/Time type parameter. Build number:2.2.0.v200704031345 Steps to reproduce: 1. New a Date report parameter. 2. Click Change... button to set format for it. Expected result: Can set format for Date/Time parameter. Actual result: Change... button is disabled. Error log:N/A
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/FormatDateTimePage.java
previewText = null;
		}
		else
		{
			previewText = text;
		}
		return;
	}
	/**
	 * @return Returns the previewText.
	 */
	private String getPreviewText( )
	{
		return previewText;
	}
	/**
	 * Sets the pattern string for this preference.
	 * 
	 * @param pattern
	 *            The pattern to set.
	 */
	private void setPattern( String pattern )
	{
		this.pattern = pattern;
	}
	/**
	 * @param datetiem_format_type_general_date
	 */
	private void setCategory( String category )
	{