class TGLineWidthComboBox: public TGComboBox

TGComboBox, TGComboBoxPopup

A combobox (also known as a drop down listbox) allows the selection
of one item out of a list of items. The selected item is visible in
a little window. To view the list of possible items one has to click
on a button on the right of the little window. This will drop down
a listbox. After selecting an item from the listbox the box will
disappear and the newly selected item will be shown in the little
window.

The TGComboBox is user callable. The TGComboBoxPopup is a service
class of the combobox.

Selecting an item in the combobox will generate the event:
kC_COMMAND, kCM_COMBOBOX, combobox id, item id.