Im having a strange problem here. I have created a figure in photoshop, on multiple layers with no animation. Imported into after effects as composition fine, but the composition and individual layers cannot extend beyond 2 frames.
They can be reduced to just one frame but not beyond the 2 frame mark. Each layer has black tabs in the top right and left corners of the "colour visual layer thing".
Depending on various things such as your preferences settings (still image import length) and composition settings, it is possible to import a PSD as a comp, put that comp inside of another and not be able to extend its length because the comp that was created when the PSD was imported is shorter than the length you want its layer to be in the comp you put it into ... sorry it sounds confusing when trying to explain without without being able to show what's wrong, but it's really a very simple thing with a simple fix ... increase the length of the comp that was created automatically when the PSD was imported ... and check your preferences to avoid the same issue in the future.