I have two listboxes : listbox1 containing lines,and listbox2 containing cercles. And i have a button "Set" (as described in the image) to set the thikness of the selected item(line or circle). So, in the function "Set" it's written this : num =handles.selected % the value selected by the cursor is called num. e(num)=thiknss % Then we give this value a thikness. Now my problem is that i want to know from which box the "num" is selected.I need to know if it's from the box 1 ( a line) or the box2 (a circle). How can i do that?