please tell me how to move the old time line to the left

i cant see this in GB 10. the playhead cursor line that was at the end of the time line that one had to move to define the song length

not the playhead

but the cursor that hid in GB 11 on the upper right to bring a song to its end by moving it to the left so that the song ended when it indeed ended

i have a song in GB 10 with 899 bars

how do i get this line to shift the song to the very last bar 90 bars

cant find it anywhere

please

this is so frustrating