.fi
.ll 60
.pl 5
.ce
A-CTRL & B-CTRL BUTTONS

In the right-hand sidepanel there are three buttons: CLEAR, A-CTRL and
B-CTRL.  The button CLEAR is used to clear the panel.  The other two
are used when two BPL files are simultaneously displayed and each has
more than one member (more than one frame).  Given that one BPL file 
has been loaded into the
Model A channel and another into the Model B channel, enabling their
simultaneous viewing can be accomplished by a selection from the
"View" menu (example: menu item '3D A & 3D B').  Selection of the
Model A frame to be so viewed is enabled by the A-CTRL button and
selection of the corresponding
Model B frame is enabled by the B-CTRL button. 

.ce
THE END
