You may know that you can switch between sequences in the Timeline and Canvas windows using the shortcuts for selecting the previous tab Command-Shift-[ and the next tab Command-Shift-]
You may not know that you can also do this in the Viewer as well.
To open a clip from the timeline, you can press return.
To switch between the Video, Audio, Filters and Motion tabs from the keyboard, use the same shortcuts.
You can bring up the Motion tab while looking at the Video tab by pressing Command-Shift-[ in the example below, you can switch from the Filters tab to the Color Corrector 3-way tab by pressing Command-Shift-]