some more testing:
The random placement mode behaves normal: it uses both outputs when "place across all outputs" is selected, and also works like its supposed to with any other multi output mode.
Smart testing reverts to the top left corner of the second monitor if it is active and "use active output device" is selected for multi output mode. if "place across all outputs" is used, the second monitor is ignored and only the first one is used.
additional info:
this behaviour appears in ubuntu 12.04. older versions (11.10 and before) did not have this bug.
some more testing:
The random placement mode behaves normal: it uses both outputs when "place across all outputs" is selected, and also works like its supposed to with any other multi output mode.
Smart testing reverts to the top left corner of the second monitor if it is active and "use active output device" is selected for multi output mode. if "place across all outputs" is used, the second monitor is ignored and only the first one is used.
additional info:
this behaviour appears in ubuntu 12.04. older versions (11.10 and before) did not have this bug.