# Multiple Tree Controls

> [HTML Version](multipletreecontrols.htm)

You may have multiple XTREE controls defined and displayed at once. To do so, you must specify a unique control number (0=first, 1=second, etc.) in the XTR\_CTLNO parameter, and use the flags XTF\_MODELESS option (so that you can exit the first list without destroying it). This kind of arrangement can be useful for allowing the user to move items between two categories, or to present in one list box a set of possible items, and use the other to store the ones that have been chosen.

See [XTR.CTLNO](xtr_ctlno.htm.md) for information on auto-assigning a control number.

See also [Scenarios Involving Multiple Trees](scenariosmultipletrees.htm.md).