Hi David,
Unfortunately you cannot embed controls into a list box, so it's not possible to obtain the desired efect this way. What you can do is to trap some event on the list box and operate consequently. Usually I put a callback on the control and trap the right-click event, next from mouse cursor I determine the row clicked on and run a popup menu with a list of options for that particular item: I should have put an example of this somwhere in the forum but now I cannot find it back. Later I will post one, it's only a few lines of code.
As per the syntax of the item, its description lies somewhere in the help for the library: I'll be more precise when I came in my office, but here some hint: all items start with a \033 that instructs the listbox that what follows is a special code.
\033p%dl: "p" means pixels, %d is the amont of pixels required (you could write it down in clear if it's constant) and "l" means left-align (you could use "c" as well as "r" with obviour meanings). So \033p120l states that the following text will be written at 120 pixels position and left aligned
\033vline means insert a vertical bar at the cursor position (set by the previous \033p statement)
There are also a few other control codes for determining color of text: you'll see in the documentations.
Hope this helps
Roberto