Column with filename becomes hidden because of quotes misplacement

[imThief]

Hello

The subj is clearly visible on the screenshot: because of misplaced quotes browser treats any words in filename after first space as html tag's options. Because of that whole element becomes "hidden" if the filename contains such word.

I guess something one of this should do the trick:
<td data-sort="<?php echo fm_enc($f) ?>">
<td data-sort=<?php echo '"'.fm_enc($f).'"' ?>>
<td data-sort=<?php echo fm_enc(str_replace(' ','_',$f)) ?>>