iables of a predicate in the edit window will highlight
this variable with green underline, other associated variables (with same
sort) will be also highlighted but with red under line.</tt></li>

<li>
<tt>Right click on the green underlined variable will bring up a menu to
rename this variable (Figure 5).</tt></li>

<li>
<tt>Right click on the red underlined variable will allow user to choose
from three options: same, different, optional (Figure 6).. Choose "same"
will set this red underlined variable to b