Dialog to select multiple waves?

Hi dear Igor-people,

I would like to make a dialog where a user can select multiple waves, which should all receive some treatment (i.e. become input of a function for analysis or custom smoothing).
The ideal scenario would be this:
1) A user is inspecting a graph with several traces, then decides that one or more traces should receive some treatment.
2) The user starts a function which displays a list of tracenames or wavenames on the graph, multiple of which can be selected. Press ok, all selected waves are passed to the proper function.

This is all quite doable, in the case of a drop-down menu which allows me to select one tracename/wavename. I have not yet programmed this simple, one-item case, but I am confident that will work with the great documentation and my experience so far.

My question is, can users program an interface which allows selection of multiple items, similar to the way this can be done in the 'New Graph'-dialog?

A sincere thanks!