Question

If I rewrite a block and developer mode is active, the standard translation is not displayed any more. How can I make Magento to fall back to the original translation of the module.

This is related to Magento: Avoid loss of translations when rewriting controllers

Answer 1

It is possible to overwrite the module name in the block which is used to determine which translations should be used:

class Acme_GreatModule_Block_Customer_Account_Navigation extends Mage_Customer_Block_Account_Navigation
{
    /**
     * Set the original module name to avoid breaking translations
     */
    public function __construct()
    {
        parent::__construct();
        $this->setModuleName('Mage_Customer');
    }     
...