What kind of children are you adding to the TabBar? I have a tabbed
based app where the children all extend Panel and are located in
separate MXML files. I simply set the toolTip="Custom tooltip text" in
the attribute of the root MXML tab and each child shows its own
tooltip when hovered. Is that what you're looking for? Even if you're
creating and adding the children in AS you should be able to set the
toolTip for each one to the string you want. The components will
handle displaying their tooltips on their own.