Kid 0 - XuiListButton
"Selection" callback when XuiList item selected
v0 : item - 0 is topmost item
Kid 1 - XuiTextLine
"Selection" callback from Enter KeyDown when grid has focus
v0 : item if text string is also in XuiPullDown list, else -1
Kid 2 - XuiPressButton
XuiListBox grids display a text string in the XuiTextLine grid, and a list of items in an XuiList grid window that toggles up and down when the XuiListBox button is selected.
XuiListBox grids generate Selection callback messages when the user presses an Enter key when the XuiTextLine has keyboard focus, and when the user selects any item in the XuiList grid.
The XuiDropBox grid manages the XuiList window, so the XuiList items are the TextArray property of the XuiListBox.
