I'm having a couple of problems.  First off, I am using JasperSoft iReport version 3.7.1 selecting Gantt chart from the Widgets Pro item of the Palette. 
  
Through trial and error and hunting for info, I finally had my charts looking something like the first one (where each user has their own chart)... see sched chart 1.jpg  
but I was confused as to why I was getting the tasks lined up correctly but an extra "blank" row.  I was assigning the second column, the task-group "scheduled shift" "logins" and "pauses" as processes to the tasks. 
so after reading http://www.fusioncha...tMultiTask.html I decided maybe my users should be the processes, and the taskgroupings should be some grouping of the tasks, but I don't seem to have done it right - see sched chart 2.jpg  
  
my data is going to be coming from database queries, although for testing I just made a test dataset. 
For the end result, I need to have a dynamic start and end for the timeline, that I'll get from report parameters. So I can't manually define the categories. The dialog box for the categories says: 
"You can specify the entire list of Categories providing an expression. It must return a List of CategoryData objects." 
  
What must I pass in? What exactly are CategoryData objects? I can't seem to find any documentation for this.  What I want to have is my timeline have a user-input start and end, and that timeline broken out automatically into one-hour segments (categories).  How can I achieve this? 
  
the pics are attached, it won't let me upload .jrxml files so here is the code for the widgets: 
code that produced sched chart 1.jpg: 
					<fw:ganttChart xmlns:fw="http://jaspersoft.com/fusion"'>http://jaspersoft.com/fusion" xsi:schemaLocation="http://jaspersoft.com/fusion http://jaspersoft.com/schema/fusion.xsd" useTime="true"> 
						<fw:widgetProperty name="dateFormat"> 
							<fw:propertyExpression><![CDATA["HH:mn:ss"]]></fw:propertyExpression> 
						</fw:widgetProperty> 
						<fw:widgetProperty name="showFullDataTable"> 
							<fw:propertyExpression><![CDATA[boolean.FALSE]]></fw:propertyExpression> 
						</fw:widgetProperty> 
						<fw:categorySet> 
							<fw:category> 
								<fw:startExpression><![CDATA[new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2011-05-02 00:00:00")]]></fw:startExpression> 
								<fw:endExpression><![CDATA[new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2011-05-02 23:59:59")]]></fw:endExpression> 
								<fw:labelExpression><![CDATA["Sample Category"]]></fw:labelExpression> 
							</fw:category> 
						</fw:categorySet> 
						<fw:processes> 
							<dataset resetType="Group" resetGroup="user"/> 
						</fw:processes> 
						<fw:tasks> 
							<dataset resetType="Group" resetGroup="user"/> 
							<fw:task> 
								<fw:taskProperty name="color"> 
									<fw:propertyExpression><![CDATA[$F{process}.equals("scheduled shift") ? new java.awt.Color(-13395457): 
$F{process}.equals("logins") ? new java.awt.Color(-10040320): 
new java.awt.Color(-6710887)]]></fw:propertyExpression> 
								</fw:taskProperty> 
								<fw:idExpression><![CDATA[$F{task}]]></fw:idExpression> 
								<fw:process> 
									<fw:idExpression><![CDATA[$F{process}]]></fw:idExpression> 
									<fw:labelExpression><![CDATA[$F{process}]]></fw:labelExpression> 
								</fw:process> 
								<fw:startExpression><![CDATA[$F{startDate}]]></fw:startExpression> 
								<fw:endExpression><![CDATA[$F{endDate}]]></fw:endExpression> 
								<fw:labelExpression><![CDATA[""]]></fw:labelExpression> 
							</fw:task> 
						</fw:tasks> 
					</fw:ganttChart> 
  
--------------------------------------------- 
code that produced sched chart 2.jpg: 
				<fw:ganttChart xmlns:fw="http://jaspersoft.com/fusion"'>http://jaspersoft.com/fusion" xsi:schemaLocation="http://jaspersoft.com/fusion http://jaspersoft.com/schema/fusion.xsd" useTime="true"> 
					<fw:widgetProperty name="dateFormat"> 
						<fw:propertyExpression><![CDATA["HH:mn:ss"]]></fw:propertyExpression> 
					</fw:widgetProperty> 
					<fw:widgetProperty name="showFullDataTable"> 
						<fw:propertyExpression><![CDATA[boolean.FALSE]]></fw:propertyExpression> 
					</fw:widgetProperty> 
					<fw:categorySet> 
						<fw:category> 
							<fw:startExpression><![CDATA[new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2011-05-02 00:00:00")]]></fw:startExpression> 
							<fw:endExpression><![CDATA[new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2011-05-02 23:59:59")]]></fw:endExpression> 
							<fw:labelExpression><![CDATA["Sample Category"]]></fw:labelExpression> 
						</fw:category> 
					</fw:categorySet> 
					<fw:processes> 
						<dataset/> 
					</fw:processes> 
					<fw:tasks> 
						<dataset/> 
						<fw:task> 
							<fw:taskProperty name="color"> 
								<fw:propertyExpression><![CDATA[$F{taskgroup}.equals("scheduled shift") ? new java.awt.Color(-13395457): 
$F{taskgroup}.equals("logins") ? new java.awt.Color(-10040320): 
new java.awt.Color(-6710887)]]></fw:propertyExpression> 
							</fw:taskProperty> 
							<fw:idExpression><![CDATA[$F{task}]]></fw:idExpression> 
							<fw:process> 
								<fw:idExpression><![CDATA[$F{process}]]></fw:idExpression> 
								<fw:labelExpression><![CDATA[$F{process}]]></fw:labelExpression> 
							</fw:process> 
							<fw:startExpression><![CDATA[$F{startDate}]]></fw:startExpression> 
							<fw:endExpression><![CDATA[$F{endDate}]]></fw:endExpression> 
							<fw:labelExpression><![CDATA[""]]></fw:labelExpression> 
						</fw:task> 
					</fw:tasks> 
				</fw:ganttChart>