If you check any list view in VirtueMart 3 backend under Joomla 3 and try to order a list by clicking on the column header the tooltip of the header displays with 100% width.
Here is a screenshot: http://i.imgur.com/T1l0IQw.png
You can't see the mouse cursor but it's over the 'Manufacturers' column header and the tooltip is too wide.
It works well with Joomla 2.5
http://forum.virtuemart.net/index.php?topic=79800.0
Sorry, you're right.
So it happens since I've changed to Joomla 3. The screenshot was made with Joomla 3.4.1 and VM 3.0.8.
I also checked the source to check the classes of the tooltip.
This is a VM3 tooltip with Joomla3
(http://i.imgur.com/54V1YwB.png)
This is a VM3 tooltip with Joomla2.5
(http://i.imgur.com/zQ0Cevi.png)
This is a tooltip with Joomla 3 Content component
(http://i.imgur.com/8yzg8J5.png)
I hope it helps
IIRC some changes like that were made in order to accommodate users with older IE browsers. The tooltip shows only on mouseover so is not a problem for me.