TYPO3 Core

We can't use logical operators AND, OR in sheet displayCondition like :

<T3DataStructure>
<sheets>
    <test_sheet>
    <ROOT>
        <TCEforms>
            <sheetTitle>test sheet</sheetTitle>
            <displayCond>
                <OR>
                    <numIndex index="0">FIELD:sDEF.what_to_display:=:LIST</numIndex>
                    <numIndex index="1">FIELD:sDEF.what_to_display:REQ:false</numIndex>
                </OR>
            </displayCond>
        </TCEforms>

To fix, need refactoring of TYPO3\CMS\Backend\Form\FormEngine -> getSingleField_typeFlex :
http://api.typo3.org/typo3cms/current/html/_form_engine_8php_source.html#l02809

Discover all conditions (can be recursive : a and (b or c)) and calculate $fakeRow.