Leaving a text field to enter a keyboard shortcut

Is there a way to leave a text field (e.g. White balance Kelvin) in the tools menu and put the focus back on the viewer?

I'm using mainly the keyboard to make my adjustments in the tools menu. I then want to jump back to the viewer and for instance want to view the uneditet version of the picture by pressing "Y". But once the cursor is in one of the text fields of the Tools menu I can't bring it back to the viewer without using the mouse (and click on the viewer). The obvious keys like "ESC" or "Enter" won't work here.

Am I missing something?

Thanks!