Hi,
when 2 fleets with different missions share the same coordinates like in this example:
Example Screenshot:
http://prntscr.com/kfzpmqThen you only have 1 "sending" button. Which fleet is chosen is kind of random but you definetely have NO CONTROL and for me it always selects the fleet I do not want to send... Then I have to manually search it in the fleet menu or the fleet drop down list.