Created attachment 164241 [details]
Dia example file

Hi,

at Debian, we found the following:

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Lines connectig classes in UML diagrams look OK unless classes are aligned. In this case, multiplicity labels (like 1..*) move over the class box itself. It only happens when classes are perfectly aligned (i.e., via Object->Align menu). If you move the class object just one tiny bit, the label will  be displayed properly again.

[Further explanation:]

- swith off the snap to grid option.
- ramdomly place both classes with the mouse (just to ensure they are 
not aligned)
- slowly move one of the class objects with the arrow keys, trying to 
make the association line as straigth as possible.
- eventually, the labels will scramble.
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I can reproduce this.

See also http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=571250

I'm attaching a dia example file and the contents of the resulting window as png.

Thanks for considering.

bye,
  Roland