TYPO3 Core

In our extension we have a record with the possibility to add tt_content elements inline (IRRE). However, on the first content element you add, in IE8/9/10 the RTE (rtehtmlarea) just keeps loading with the message:

The editor is being loaded. Please wait...

After saving the record with the newly created content element the RTE loads correctly. The problem only occurs in IE8/9/10. The problem doesn't occur in Chrome and Firefox (tested on OS X).

In other, possibly related, issues there are clues for rewrite rules and custom RTE CSS files, but we don't use both of them.

Part of the TCA configuration for this record:

'content' => array(
    'exclude' => 0,
    'label' => 'LLL:EXT:<extkey>/Resources/Private/Language/locallang_db.xlf:content',
    'config' => array(
        'type' => 'inline',
        'foreign_table' => 'tt_content',
        'size' => 1,
        'minitems' => 0,
        'maxitems' => 1000,
        'appearance' => array(
            'collapseAll' => 0,
            'levelLinksPosition' => 'top',
            'showSynchronizationLink' => 1,
            'showPossibleLocalizationRecords' => 1,
            'showAllLocalizationLink' => 1
        ),
    ),
),