Description:
When I try to open a large file (~18mb) that is delimited by tab, sometimes it takes calc a very long time to open.  I noticed if I have tab as one of the default delimiters already checked off, then opening the file only takes a few seconds, but if tabs are unchecked it can take more than 30 minutes!  For larger files I've waited more than an hour before giving up and killing the process.  

I just found out I could work around this problem by first opening a small tab delimited file, making sure to check off the tab checkbox, closing calc, then opening the large tab delimited file.  

For small files, when you open delimited txt you can usually fiddle with the checkboxes on the loading screen to see which delimiter to use.  I'm guessing Calc is running into problems populating that preview table.  Maybe it's  reading the entire line(or the entire file), not running into any expected delimiters so it thinks there's just one super sized cell,then it's getting stuck trying to allocate memory or initializing the sheet with default values of those super sized cells?  When tab is already one of the default delimiters it takes less than a second to populate the preview panel.  



Steps to Reproduce:
1.  have a large tab delimited file
2.  try to open it when tab is not checked off as one of the default delimiters
3.  wait 

Actual Results:
Takes too long to load.  Usually I have to kill the process before then.

Expected Results:
It should have opened in a few seconds


Reproducible: Sometimes


User Profile Reset: No



Additional Info:
Version: 6.0.5.2
Build ID: 1:6.0.5~rc2-0ubuntu0.14.04.1~lo1
CPU threads: 8; OS: Linux 4.4; UI render: default; VCL: gtk2; 
Locale: en-US (en_US.UTF-8); Calc: CL