Hi. I installed xtra with Demo files.
Now i try to edit style. I can save but nothing change and settings goes to default. If i try copy (customizer) an save ....saving failed.

First at all, make sure that your template files are writable.
Changing File Permissions

So how do you change the permissions for files and directories? Here are two step-by-step guides.
Using your FTP client

1.) Open your FTP client or if you don't have any download FileZilla and install it.
2.) Use your FTP client to login to your server and browse to your webroot directory.
3.) Right click on a directory which you want to change the permissions on and click File Permissions....
4.) The Change File Attributes dialog, let's you check the options as shown below or type a numeric value like 755. Make sure the Recurse into subdirectories option is checked. Then hit the OK button.

If the files are writeable check this
Check the Magic Quotes status. It must be OFF.
When it is ON, just add the code in your joomla .htaccess file:

php_flag magic_quotes_gpc Off
php_value magic_quotes_gpc Off