I'm trying to create my own conf files for TeX and noweb, so I try to create config files in a "step by step" fashion.
1) I've copied usr/share/geany/filetypes.
latex as ~/home/.config/geany/filedefs/filetypes.tex.conf
2) i've commented out in the file filetype.extensions,.conf the line
  LaTeX=*.tex;*.sty;*.idx;*.ltx;*.latex;
and I've adde the line
  TeX=*.tex;*.aux;
3) I've added in the file ~/home/.config/geany/filedefs/filetypes.tex.conf
the line
  lexer_filetype=latex
in the [settings] section
but at this point the ~/home/.config/geany/filedefs/filetypes.tex.conf is not read. If I open a .tex file I found a menu option <document - set filetype - tex file> but hitting that menu option the document loses his syntax highlighting.

Were is my fault?

Many thanks.