Yeah, it was intentional to avoid browser crashes years ago with very large tables.  50 was somewhat arbitrarily chosen, at the time.  We could make this configurable for galaxy instances and/or increase it outright.  Here's the logic in question, if you wanted to tinker with it:
https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/datatypes/tabular.py#L90

On Fri, Jun 1, 2018 at 10:04 AM Matthias Bernt <m.bernt@ufz.de> wrote:
Dear Dannon,

its 59 columns :( the last columns are only sometimes 0.

Is there a performance issue when rendering html tables with a larger
number of columns?

What would be the Galaxy way to handle data with a larger number of
columns?

I agree that the scidx problem is unrelated. Might be worth to open an
issue?

Best,
Matthias

On 01.06.2018 15:44, Dannon Baker wrote:
> I'm not familiar with MetaProSIP, but how many columns *should* be in
> the output?  Galaxy automatically displays tabular data with more than
> 50 columns in the 'raw' view you're seeing here, instead of using a
> table.  The last bit of data in particular, when looking at the sample,
> is a ton of `0` columns.  Is that correct?
>
> One more possible issue is that this is sniffed as a `scidx` file, for
> me, though that's unrelated to the display problem here.
>
> -Dannon
>
> On Fri, Jun 1, 2018 at 9:03 AM Matthias Bernt <m.bernt@ufz.de
> <mailto:m.bernt@ufz.de>> wrote:
>
>     Dear list,
>
>     I'm struggling with tabular data in Galaxy. Attached is a tab separated
>     file that is generated by MetaProSIP (an updated - not yet committed --
>     version).
>
>     The problem is that it is not shown as table in Galaxy (dev) at all.
>     Also the peek preview is odd, some values of the header and data are
>     omitted.
>
>     Is this a bug in Galaxy, or of the data in the table?
>
>     Cheers,
>     Matthias
>     --
>
>     -------------------------------------------
>     Matthias Bernt
>     Bioinformatics Service
>     Molekulare Systembiologie (MOLSYB)
>     Helmholtz-Zentrum für Umweltforschung GmbH - UFZ/
>     Helmholtz Centre for Environmental Research GmbH - UFZ
>     Permoserstraße 15, 04318 Leipzig, Germany
>     Phone +49 341 235 482296,
>     m.bernt@ufz.de <mailto:m.bernt@ufz.de>, www.ufz.de <http://www.ufz.de>
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--

-------------------------------------------
Matthias Bernt
Bioinformatics Service
Molekulare Systembiologie (MOLSYB)
Helmholtz-Zentrum für Umweltforschung GmbH - UFZ/
Helmholtz Centre for Environmental Research GmbH - UFZ
Permoserstraße 15, 04318 Leipzig, Germany
Phone +49 341 235 482296,
m.bernt@ufz.de, www.ufz.de

Sitz der Gesellschaft/Registered Office: Leipzig
Registergericht/Registration Office: Amtsgericht Leipzig
Handelsregister Nr./Trade Register Nr.: B 4703
Vorsitzender des Aufsichtsrats/Chairman of the Supervisory Board:
MinDirig Wilfried Kraus
Wissenschaftlicher Geschäftsführer/Scientific Managing Director:
Prof. Dr. Dr. h.c. Georg Teutsch
Administrative Geschäftsführerin/ Administrative Managing Director:
Prof. Dr. Heike Graßmann
-------------------------------------------