Sigil 1.4.2
Windows 10 Pro
I checked this EPUB file in Turkish and clicking on a word in the spell checker correctly jumps to the right place in the .xhtml file.
Are you sure you have the Turkish dictionary installed?
There are two files:
tr_TR.aff
tr_TR.dic
Download them from here:
https://github.com/LibreOffice/dicti...e/master/tr_TR
... and make sure you put the files in the dictionary folder:
%localappdata%\sigil-ebook\sigil\hunspell_dictionaries