Function Handle Callbacks and appdata

I am having a hard time updating a list from a function callback. For instance, I pass the handle of a line to the function line_edit and the user selects a color to change the line. That all works fine but I cant add the new color value to a listbox for display in my GUI

Here are some snippets of code:

line_handle = plot(gca,f,pxx);
set(line_handle,'ButtonDownFcn',@line_edit);

function line_edit(src,evnt)
  color_current = str2num(get(handles.color_table,'String'))

%%I use ismember and find to find where user_selected_color and current_color have matching rows. %%then I would want to update color_table but the handles funcions arent defined

Summary: How do I pass the handle of another object into my function? how and where should i store this data

[Chad]

Figured it out. used findobj inside the function