Here is the code for the dialog:
Begin Dialog UserDialog 100, 75, 375, 65, "Pick your file"
ButtonGroup .ButtonGroup1
Text 9, 3, 100, 13, "Filename/Copyib/Member:", .Text1
DropListBox 5, 15, 350, 500, filenames(), .DropListBox1
OkButton 10, 45, 42, 13...