[Bug-gnubg] minor enhancement

[Azad Bolour]

Hi,

Thank you for your excellent backgammon program. I am learning
a great deal by using the tutor and the analysis functions of gnu backgammon.

A minor issue.

When one needs to do a rollout, if a number of possible moves are selected
in the rollout window, and then one changes the rollout parameters,
the selection is lost in my version of gnu bg for windows 0.13, 2/15/93.
Similarly after a rollout is completed the selection in the main rollout
window is deselected.

I am not sure if there is a reason for this. If not, it would be helpful
if the selections remain selected after such operations, so they can
be redone with new parameters.

Many thanks.

Azad Bolour