I don't need the light numbering function.
It is frustrating to click on a light and the black
square appears there with a small number out in the field.
Even when I select the light or click in the field to get rid of the black
square, the small numbers remain on the plot either in the light
or somewhere in the field. Can I disable this function?
Light numbering
If you completely don't want your units to be automatically be numbered you can shut that off using the Automatic tab of the preferences. (View->Options in LXFree for Java) Another option that may help the accidental drag of displayed info fields is to shut off the ability to select them using Format->Disable Info Field Selection. Note that when this option selected, it is still possible to select an info field by holding down the alt key and clicking on it.