If you don't need virtualLayout, I think you can turn it off and every
renderer will be created and the correct measured size will be calculated.
If you need virtualLayout, you might try using the typicalLayoutElement in
the layout to compute the widest element.
Another option is to use a Label somewhere to measure the text and then set
the longest item as the typicalItem.
The useVirtualLayout property, true or false, does not solve the problem.
I will put all item in a Label and get measure. What a job !
Coming from the HTML / JQuery world, I'm very surprised to not find a "autoSizeToMaxLengthItem" property in Flex because all browsers do that since 15 yeays in HTML.