How to Keep Focus of File-Browser when Previewing Thumbnails in Sushi?

Question

A report done here already 2011 in bugzilla.gnome.org but no proposals for improvement. It is possible that this is not a gnome-sushi issue but dependent on the packages on the test environment

• How can you monitor execution times started by space?
• Why does the focus change after space in the file-manager?

Test environment

• sudo apt-get gnome-sushi unoconv. Press Space on any .ppt file.
  Output: slow visualization of the first page as a thumbnail.
  Expected output: rapid visualization of the thumbnail.

Current process is slow (5-11 seconds for generation)

1. Space on file name for slow visualisation of the first page of the document.
2. Space again to stop visualization.
3. Left arrow key to see the next document.
4. Repeat (1-2) again.

Faster approach proposal

1. Press Space - slow visualization of the first page of the document starts.
2. Press the Right arrow key which I would like to moves the document in the file-browser.
3. Repeat (2) to view files fast.
4. Press Space to stop previews.

Can the proposal be technically possible in Ubuntu 16.04? Here to maintain the focus in the file-manager.