Hi!

I am an astronomy teacher, and I'm preparing a program to analyze stellar spectra with my pupils. It's going on well (I think!), but I have a strange problem that I can't solve by myself.

The principal code is in "espectro-visual.lisp" ("fits.lisp" is a kind of little 'library' to open fits image files, an astronomical standard; you can visualize them with programs like "SaoImage DS9"). You run the program with '(espectro-visual)'. To reproduce the problem I think I'd better guide you step by step:

1) You click in 'Create profile..." and choose 'solar-spectrum.fit' (you can download this file (~1MB) from http://www.astro.cnba.uba.ar/solar-spectrum.fit).

2) Then you move over the profile, and -pressing the mouse right-button- move a dozen or so pixels left or right and release the button: you'll see a line and a number under the 'barycenter' of the zone (astronomically, you should choose an spectral line (one of those 'valleys' here and there), but that doesn't matter now).

3) If you press the mouse left-button over the number created, you can move it around the canvas (I want to be able to do it, to avoid the 'cluttering' of labels).

Now, the problem: As soon as I leave the canvas with the mouse, if I re-enter the canvas I'm no longer able to move the labels again! I can do it with new labels, but if I leave the canvas the problem applies to them too.

Thank you very much, and please excuse me if I didn't explain myself very well.

Luis López