First atempt for adding to speed dial failed (second and after are working)

Hi!

I have a little problem, if I open firefox now and try to add to speed dial a website, the "create/dial" box will be shown as an incomplete box, see the image attached... If I press cancel and i try again, the proper box will show and everything is working... This problem is happening everytime when I try this action for the first time after I open firefox...

What can I do to work properly?

Thank you in advance!