Custom Chrome is Covering My Content

I am writing my first desktop app with AIR using Flex. I have created my own chrome with minimize, maximize, and gripper buttons, but the TitleBar in the chrome is overlaying some of my content at the top of the screen. I assumed that the chrome would be "outside" of the applications, and the stage would lie under it. Is this not the case? Do I have to manually figure out the dimensions of the rest of my stage/content to accomodate the title bar dimensions, or is there a setting that will force the chrome to lie "outside" of the stage?