After some work yesterday, I found some 2 hrs of time again which i used to port the enum widget to new class. The results are simply amazing :)
Hover and tooltips work for the text on the widgets now!

Now the uml-widget contents aren’t painted by single item, instead the texts are split into multiple text items. In future, a user should be able to edit the text by double clicking on any text inside widget and edit it with validation support. This will surely improve the user experience of umbrello. :-)
I can’t wait to port other uml-widgets :p
BTW I started using neon and it really rocks. I will be able to free about 8 GB space on my hard drive ;)
Thanks a lot to the neon team :)