Shift F3 not opening file in external viewer

[vsrawat]

601 on w7. seeing the additional tools on fc site, I downloaded and installed external viewer.

I have set C:\Program Files\Universal Viewer\Viewer.exe in settings - programs - External Viewer.

but, when I press f3, nothing is happening.

however, I can very much open several files from rightclick context menu's "universal viewer" click.

so, Shift F3 seems to be broken unless I missed something.

Thanks.
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Rawat