Why does Second Life (3.2.1) always open in full screen mode on a 27 inch iMac with OS X 10.6.8

[SparkySundevil]

When starting Second Life (SL) the window fills the screen.  This wouldn't be a problem, but the opening screens clickable arrows, boxes, and text do not position themselves correctly.  It seems that the black space around the grey SL window is causing issues with the clickable items.  I can use the Debug menu to "Set Window Size.." and select "1920 x 1080 (1080p)" to correct the issue for that session.  But when I quit SL and restart SL, the window fills up the screen again.  This doesn't seem to cause any issues after I log in, but that start up screen is not good.

 

System Info: Intel Core i5 2.66 GHz, 4GB Ram, and an ATI Radeon HD 4850 display card.