At now, all description an comment fileds are defined as 'varchar(4000)'. That is too short (I had to import text until >32k chars).

So I added some lines in ./view/objetctDetail.php (between lines 380 and 381)
from

(…)
			$dataLength = $obj->getDataLength($col);
			//echo $col . "/" . $dataType . "/" . $dataLength;
			if ($dataLength) {
(…)

to

(…)
			$dataLength = $obj->getDataLength($col);
			//echo $col . "/" . $dataType . "/" . $dataLength;
			if ($dataType=='text')
				$dataLength = 65535 ;
			else if ($dataType=='mediumtext')
				$dataLength = 16777215 ;
			if ($dataLength) {
(…)

This change allows to change any field format from 'varchar(4000)' to 'text' or 'medium text', the second one offering until several millions characters for texts.

Very easy to apply, and doesn't cost anything !

(At now, I have several fields added or so altered, and a lot of lines containing texts with more than ten thousand characters. All works fine !)