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Positioning dialog controls is generally a two step process, where an initial arrangement specifies the relative position of each control and then any special alignments are specified.
Dialogs items are arranged by setting an initial anchor control and then specifying a chain of controls relative to the first control. Layouts and group items are the only two objects that can have anchor controls. Anchor controls are set using either SetFirstLayoutItem or SetFirstGroupItem. The next item is placed relative to the anchor item using either SetBelowItem or SetRightItem. Using these Set*Item calls, a chain of controls can be created with each item relative to the other. Group items are just like other items in that any control including another group can be placed to the right of or below another group.
The initial arrangement generally places items so that they’re left and top edges are aligned. To specify other alignments use the AlignItemEdge call. In AlignItemEdge you specify an edge and an alignment group. All objects in the same alignment group are aligned together. AlignItemEdge also allows you specify whether you want an object to shift or resize when performing the alignment.