Bug 79843

If you click on an association label, then move it using [ctrl]+[arrow_keys]
then attempt to click on and move another association label, the first one still
has focus.

How to repeat: 

(1) Create a new diagram (tested with use case and activity). 
(2) Add three objects (use case, actor, state, etc.).
(3) Create an assoication between object 1 and object 2, naming it 'one'.
(4) Create an association between object 2 and object 3, naming it 'two'
(5) Click on association one's line. Then on the label. Observe that the label
has focus. Move it using [ctrl]+[arrow_keys]. Observe that label for association
one is moved.
(6) Click on association two's line. Then on the label. Observe that label 'two'
has focus. Move it using [ctrl]+[arrow_keys]. Observe that the label for
association two *did not* move. Observe that the label for association one *did*
move.

NOTE: If after step five, you release the [ctrl] key. Press any arrow key at
least once (causing the panel to scroll in the appropriate direction). Things
work as you would expect.