The current-time indicator (CTI) is shown at the beginning of a frame. If you’re zoomed way in in the Timeline panel, you can see a bluish-gray (at least that’s the color with my UI settings) shading for one frame after the CTI. That shading is showing you the duration of the frame that the CTI is sitting “on”—i.e., the one shown in the Composition panel.
If you really, really want to move the CTI to the very end of the timeline (i.e., to the beginning of the first frame that isn’t in your composition), then you can press Page Down to step frame by frame beyond the last frame. Of course, you’re not going to have content in your Composition panel for this frame.
For information on moving the current-time indicator, see the “Move the current-time indicator” section of After Effects Help on the Web.
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Todd Kopriva, technical editor, Adobe Systems Incorporated
putting the ‘T’ back in ‘RTFM’ : After Effects Help on the Web
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