XF 1.5 Template broken?

[FrankHeijden]

heya,

so this happened to my forum after i reverted some outdated templates to their default ones. Is there a way to fix this?

The spots covered in red are the weird things happening; my forum has always its loading icon in the top right; and the forumstyle is not loading correctly.
Also, i noticed a random copy of the [User | PM | Alerts] bar under my navigation bar.

 

[Mike]

You appear to be using a third-party style, so for any style issues, you would need to contact the author.

The constant loading icon is very likely to be add-on related, so please disable all add-ons (and style modifications) and confirm whether it continues.