Help with timeline retrimming issue AE and Cinema 4D lite

I am doing an independent study project and I need help ASAP. I have created an AE file with a C4D layer, and my instructions say to change the frames in c4d to 150 from 90. I saved the file in c4d then went back to AE, where my next step is to "retrim the out point" of the "ghosted bar (for the cinema 4d layer in the timeline). I see the arrows <--> that act like they should allow me to drag the end of the bar to the end of the clip, but when I try to move it, I move the entire bar, not extending its length. I am using the newest versions of both softwares on a mac. Does anyone know what I am talking about, what I am doing wrong, or a way to fix this? I have tried moving the cursor to the end and using the shortcut ] and it just moves the whole bar to the end.

Any help is greatly appreciated.