Can't get my UI10 field to show up

[Guido1982]

I've added a UI10 field to a block like this:

PHP Code:

        include_once('vtlib/Vtiger/Module.php');
        $module = Vtiger_Module::getInstance('LitigationMatter');
        $block = Vtiger_Block::getInstance('LBL_Parties', $module);
        
        // Setup the field
        $field                =    new Vtiger_Field();
        $field->name        =    'lm_secondclient';
        $field->label        =    'Eventueel tweede cliënt';
        $field->table        =    'vtiger_litigationmatter';
        $field->column        =    'secondclientid';
        $field->columntype    =    'INT(11)';
        $field->uitype        =    10;
        $field->typeofdata    =    'V~O';
        $field->sequence    =    5;

        $block->addField($field);
        $field->setRelatedModules(array('Accounts')); 


But the field is not showing up. I checked the DB, all seems to be well. When I change the UI type in the DB to 1, the field shows up. The field IS showing up in the 'vtiger_fieldmodulerel' table.