Gcode viewer not showing preview do I need a plugin?

What is the problem?
No image at gcode viewer tab when I click on a gcode or upload one.

What did you already try to solve it?
Search this forum, google and plugin page to see that maybe I need to enable something or install a plugin.
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
MK3 with pi zero installed on its native port.

Try clickiing on "Center Viewport On Model". Mine often shows a blank window until this is clicked.

The viewer will only show anything if you "load" the gcode file. You can do this by pressing the folder button, or during a print it should also show.

[Goodeid]'s suggestion worked, for the local loaded files, not SD. Maybe the viewer is not able to show the SD one anyways. I still had to do reload to see it and just loading did not work. Thanks!
[jneilliii]'s suggestion did not work for me, on local or SD. Still thanks!