I'm really sorry but I though my question is very basic (How can I edit ticket's subjects?)
Read below please... I wonder why this editor doesn't support table tag well
osTicket Version
v1.9.12 (19292ad)
— Up to date
Web Server Software
Apache/2.2.31 (Unix) mod_ssl/2.2.31 OpenSSL/1.0.1e-fips mod_bwlimited/1.4
MySQL Version
5.5.42
PHP Version
5.4.44
gdlib
Used for image manipulation and PDF printing
imap
Used for email fetching
xml
XML API
xml-dom
Used for HTML email processing
json
Improves performance creating and processing JSON
mbstring
Highly recommended for non western european language content
phar
Highly recommended for plugins and language packs
fileinfo
Used to detect file types for uploads