Display Input and Thumbnail

[tomczak]

Again, this is probably nitpicking, but I'm just curious if that how it should work.

If the Preview is set to Output or Side-by-Side, the Thumbnail also displays the Output.

- If one toggles the Preview from Side-by-Side to Input --> the Thumbnail changes form Output to Input
- If one toggles the Preview from Output to Input --> the Thumbnail doesn't change
- similarly, if one toggle the Preview from Input to Output --> nothing happens with the thumbnail unless the Side-by-Side button is pressed, uppon which the thumbnail changes.

[jsachs]

Fixed for next release.