TYPO3 Core

• Open the RTE
• Create a paragraph and apply multiple text styles to a part of the paragraph.
• During the saving process the classes get lost even if they are allowed.
• The same seems to work for a complete paragraph.

I've figured out that there are two problems:

In the Method HTMLparserConfig the list of allowed
tags will be overwritten with an expoded string.

Line 1256 ad 1257:

if (strcmp($keepTags[$key]['fixAttrib'][$atName]['range'],'')) $keepTags[$key]['fixAttrib'][$atName]['range'] = t3lib_div::trimExplode(',',$keepTags[$key]['fixAttrib'][$atName]['range']);
if (strcmp($keepTags[$key]['fixAttrib'][$atName]['list'],'')) $keepTags[$key]['fixAttrib'][$atName]['list'] = t3lib_div::trimExplode(',',$keepTags[$key]['fixAttrib'][$atName]['list']);

But at runtime $keepTags[$key]['fixAttrib'][$atName]['range'] contains an array, not a string. Therefor The Sting "Array" is afterwards content of $keepTags[$key]['fixAttrib'][$atName]['list'].

In my opinion we need to check first if the value is realy a string and if
not, we shouln't do anything:

Second Problem:

In the method HTMLcleaner the handling of a list need to be enhanced to allow the user to use MultipleListItems. To solve this i've introduced an configuration option "allowMultipleListItems"

(issue imported from #M12496)