How do I add connection points to UML sequence object life lines?

[Jane S]

I have a drawing with approximately 25 object life lines so far.
At the bottom of the drawing (time progressing means you move downwards in
the drawing) the object lifelines suddenly have no connection points when I
extend them.
All object life lines stop having connection points when the reach 130 in
the (unchanged) vertical ruler.
Now the Activation bars can not glue to the object life lines, because the
object life lines have no connection points.

How do I make the object lifelines automatically have connection points when
I pull them in order to extend them (beyond 130 cm down the vertical ruler)?
(so far the object life lines automatically had the connection points)

 

[Paul Herber]

I have a drawing with approximately 25 object life lines so far.
At the bottom of the drawing (time progressing means you move downwards in
the drawing) the object lifelines suddenly have no connection points when I
extend them.
All object life lines stop having connection points when the reach 130 in
the (unchanged) vertical ruler.
Now the Activation bars can not glue to the object life lines, because the
object life lines have no connection points.

How do I make the object lifelines automatically have connection points when
I pull them in order to extend them (beyond 130 cm down the vertical ruler)?
(so far the object life lines automatically had the connection points)

Each connection point has to have an individual definition so there is
a practical limit to how many can be defined.
However, use the menu
Tools -> Snap and Glue
check to see whether there are more options you can tick for glueing,
like shape vertices.