Version:           1.5.2 (using KDE KDE 3.5.2)
Installed from:    Fedora RPMs
OS:                Linux

The new feature implemented in v1.5.2 (see bug 67223) changed the behaviour of arrows linking entities together.  The problem is that the same behaviour exists in the use case diagram and it makes it very very difficult to make sensible diagrams.

e.g. a simple diagram:
in previous versions the following use case diagram would be acheivable.

           O                        O
           +                        +
           /\                       /\
         actor 1                  actor 2
             \                     /
              \                   /                   O
               \                 /                    +
                \               /                     /\
              ___V_____________V____                actor 3
             /                      \    ____,------
            '   a use case           '<-'
             \______________________/

but now, the lines will 'try' to be vertical which makes the diagram look like the following:

        O                               O
        +                               +
        /\                              /\
     actor 1                          actor 2
           |                          |
           |                          |
           |                          |
           |                          |
           |                          |                   O
           |                          |                   +
           |  ______________________  |                   /\
           V /                      \ V<--------------- actor 3
            '   a use case           '
             \______________________/

This is a simple example, but when you have a really complex use case diagram it gets really difficult to read because the horizontal and straight lines connect at points some 10 or so pixels at one corner.

I would prefer it is the use case diagrams would allow arrows to point towards the "central mass" of the use case oblong or the actor rather than to a corner. (or indeed have the option to do so) and also allow non-horizontal and vertical lines.

However, the horizontal and vertical lines are fine for class diagrams...
I hope this helps.