To change the colour of any text within MyGUI simply put in the hex colour value in the text

For example

widget->setCaption("#FF0000Red Text");
widget->setCaption("#00FF00Green Text");
widget->setCaption("#FF0000Colored #00FF00Text");

Example for a list:

list->addItem("#FF0000Red line");
list->addItem("#00FF00Green line");
list->addItem("#FF0000Colored #00FF00line");

You can colour any text used in any widget.