Currently Being ModeratedAug 17, 2012 11:35 AM (in response to Wunderboy)
I have a similar configuration (Lion 2011 MBP and SL 2009 iMac w/ second display). After installing the recent Remote Desktop update things went awry when trying to share the iMac SL displays with the MPB Lion.
The displays on the iMac are the same resolution, however the second display physically sits a bit lower than the iMac display, so I had adjusted the arrangement to compensate the different heights. The second display is located physically to the left of the iMac display, but that shouldn't have any effect as far as I'm concerned. Screen sharing had worked in this config until the recent Remote Desktop update (on Lion).
I thought about what you mentioned about the display screen arrangement, so I decided to just test it for myself, arranging both displays side-by-side on the displays arrangement control panel. Surprisingly, it worked!
I do consider the Remote Desktop update to be the culprit and there must be some bug associated with that. I'm getting ready to submit a bug report, so hopefully we'll see a fix soon.