Studio 2.1 + buddypress 1.5

Hi !
I updated To buddypress 1.5 and studio 2.1.
Everything is working perfectly,

Just a question,
On my Buddypress Activity Wall, the buttons COMMENT - FAV - DELETE and SHARE
look really ugly when I do a mouse over ...
Have a look :

Maybe it is just on my installation ??
Or is it a problem with the theme itself ?

Thank's in advance for help