I imported into my event animation sequence thousands PNG files, which where created in 3D animation software. It did not come as a one clip. After importing and selecting the project I have these stills are showing in the library browser on the top left. They are among the video and music clips. So in order to find some video other still images files I have to scroll all thousand stills to get to the right file, unless I do search. I followed Tom's suggestion and created an event and moved all the stills into that event.
In FCP7 I used to create a folder, and placed all the stills inside, so they were out of my way. Hope this explains, and thanks for Luis.your help,