Hi, I made all the written procedure in osclass site tatiana theme by mistake.

before


          <div class="row">
            <label for="regionId"><?php _e('Region', 'tatiana'); ?></label>
            <?php $go_reg = osc_is_web_user_logged_in() ? osc_user() : $def_reg; ?>
            <?php ItemForm::region_select() ; ?>
          </div>
          <div class="row">
            <label for="city"><span><?php _e('City', 'tatiana'); ?></span><span class="req">*</span></label>
            <?php $go_city = osc_is_web_user_logged_in() ? osc_user() : $def_city; ?>
            <?php ItemForm::city_select() ; ?>
          </div>

after


          <div class="row">
            <label for="regionId"><?php _e('Region', 'tatiana'); ?></label>
            <?php $go_reg = osc_is_web_user_logged_in() ? osc_user() : $def_reg; ?>
            <?php ItemForm::region_select(osc_get_regions(osc_user_country_code()), osc_user()) ; ?>
          </div>
          <div class="row">
            <label for="city"><span><?php _e('City', 'tatiana'); ?></span><span class="req">*</span></label>
            <?php $go_city = osc_is_web_user_logged_in() ? osc_user() : $def_city; ?>
            <?php ItemForm::city_select(osc_get_cities(osc_user_region_id()), osc_user()) ; ?></div>

@Antimo
You can see that function osc_user_country_code does not exists.

What should I bring?

@Antimo
Create this function, if you want to use it.

can you help me?

@Antimo
With this one not, you need to check for code on osclass forums.

Hello, also in the My Profile page does not work the region selection, I checked on your demo is working, perhaps because in that you download the selezine country is not there. Let me know

@Antimo
Do you use latest theme version?

I, use the latest version

@Antimo
Go to file:
oc-content/themes/tatiana/user-profile.php

Find code:
<?php if(count($country) == 1) { ?>style="display:none;"<?php } ?>
and remove it.

Make sure to not remove other > signs

Does not work, the same problem does even when I enter the selection item_post ...

@Antimo
Then it is bug of your osclass installation.
In all our themes is used same code:
<?php UserForm::region_select($user['fk_c_country_code'] <> '' ? osc_get_regions($user['fk_c_country_code']) : '', osc_user()) ; ?>
If region_select does not return you list of regions, then it is problem you need to fix.
You may try to check source code to see this, it is still possible that select box is just disabled.

Hello, the code is the same as mine, I tried it with another theme and everything works. Can you help me

@Antimo
PM us:
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I sent you a private message with the access. Thank you