The Def property can be used to define your type of bars, or specify the values for ItemBar property when a new bar is added. The Def property has no effect for already added bars. For instance, you can set the Def(exBarCaption) so all added bars will display the caption giving a specified format. You can always use the ItemBar property to specify any property of the existing bar, while the Def property can define the default values for specified properties. Let's say you need to specify the ItemBar(exBarKeepWorkingCount) property for your bars, so they will keep their working units, while moving, so instead calling the ItemBar(exBarKeepWorkingCount) for each added bar, you can have the Def(exBarKeepWorkingCount) = True, and so any new bar to be added, will have this property set, so the ItemBar(exBarKeepWorkingCount) will gets True, for all new bars.

For instance the Bar.Def(exBarCaption) = "<b><%=%9 + '/' + %C0%></b><br>Duration: <%=(%2-%1)%><br>Working: <%=%258%><br>Progress: <%=round(100*%12)+'%'%>" specifies that the bar's caption as in the following screen shot:

In the same manner, you can define the bar's tooltip such as: Bar.Def(exBarToolTip) = "<b><%=%9 + '/' + %C0%></b><br>Duration: <%=(%2-%1)%><br>Working: <%=%258%><br>Progress: <%=round(100*%12)+'%'%>"