Project panel won't allow me to scroll through my clips -- cannot see all the files I imported

Simple but aggravating prolem:  I imported all the clips for a project, and now want to drag and drop from the project panel to the timeline (as usual).  But the panel does not allow me to scroll.  I can see only a few clips, which makes it kind of hard to edit!

Have I missed some obvious setting? 

Thanks!

[Moderator note: please include your images directly into your post by drag/drop onto the reply or use the picture icon to upload. Do NOT "link" to images, as that requires users to download strange files onto their machines. I fixed this for you in this post.]