There’s a thumbnail column with the Final Cut Pro browser. Call that column up and you can then scrub the thumbnail right in the Browser column.
First you have to be sure you are displaying the Thumbnail column in a FCP browser bin. Right + click on a column heading and choose the Show Thumbnail option:
Once that is selected there will be a tiny thumbnail for each clip. It’s small but it’s actually big enough to get an idea of what might be in a clip. To scrub you just click and drag the mouse pointer:
This can be a very quick way of refreshing your memory as to what’s in a particular clip or possibly looking for a particular object in a clip. That is if that object is big enough to find in the small thumbnail frame. And it’s also worth noting that if you have a clips labeled with a color label that color goes away as you scrub the thumbnail, making it easier to see. Now if only we could make those thumbnails bigger …