Hi Ihor.

The heading and first lines of the table:

|-------------------+---------------+-----------------|
| NPS (~\Oslash_int pulg.) | DN (~\Oslash_int mm) | PP/PE (\Oslash_ext mm) |
|-------------------+---------------+-----------------|
| 1/8"              | DN 6          | PE 10 / PP 10   |
| 1/4"              | DN 8          | PE 12 / PP 12   |
| 3/8"              | DN 10         | PE 16 / PP 16   |

The \Oslash appears as the Unicode character ⊘ normally.

The \Oslash is not viewed as the Unicode character ⊘ with "org-table-header-line-mode". And the first line of the table appears in the heading.

https://i.ibb.co/jht3HL0/Captura.png

The \Oslash appears as the Unicode character ⊘, if using the package org-table-sticky-header wich has the same objective, I think:

"...this package uses the header line to show the table header when it is out of sight."

https://i.ibb.co/T8fD3BR/Captura.png

Best regards

Ypo <ypuntot@gmail.com> writes:

When enabled org-table-header-line-mode, the LaTeX symbols in the header 
are not fontified.

It would help if you provided a reproducer.

Note that getting this right is a bit tricky. In particular, when table
columns are shrunk.

The function doing the work is `org-table-row-get-visible-string'.
I am wondering if there is a better way to retrieve visible string than
what is done in the function.