by the way its not a bug as 3.7.1 works fine for me
check your notices in your admincp, found on the left, open notices manager
it might be a problem with your script as mine is working fine.
see your notices and if you've edited it in any way, The 3.7.1 script is working fine for me and this might be due to a mod you have or the script you installed or templates editing contains error
disable all modifications and see what happens, or update the navbar & header template with original that you backed up (if you have).
I hope your talking about the "Klaar" bit! if not then its just the style lokking slightly different in both browsers
back to the problem.....
The problem also might be with the style your using, the navbar or header template has an error in it, or your using an old style not compatible with 3.7.1
its more likely because of the script install, an error in the navbar or header template, an error because a mod you have installed is'nt compatible or clashes with vbulletin notices, or just simply because you edited the templates so much you don't know where you went wrong( I read your other problems and I realised you edit alot of your templates so don't blame it to being a bug.......it might be because of you editing the templates and going wrong with the style.......I hope you've been backing up your templates cause you might have to update the whole script again.
Next time please be more specific on what you've done before this comes up.....the first pic you showd is not the same as the other pic with different style, you have to give more info on what you've done before this problem occured so you can round up a single solution instead of getting multiple options that might be the problem like you just have got.