Gui

I am still learning LSL and would like to know if is possible to come up with a drop-down list by right-clicking on the object. Basically I would like to assign task to different objects. Anyone with an idea or just a simple script to build a GUI. My goal is to assign different task to different objects and sometimes work on the same task. How can I do that? I want to be able to assign and remove tasks anytime. Any idea please.