I’m seeing some strange effects within Firefox also, so it may not be restricted to any particular browser. It’s quite possible this is due to a conflict somewhere – can you try the following steps:
* Switch back to a default and unmodified theme such as Twenty Twelve
* Deactivate all other plugins except those by Modern Tribe
* Does this solve the problem?
* If so, reactivate each component one-at-a-time, checking at each stage to see if the problem has returned
* Take note of whichever component, whether your theme or a plugin, causes this behaviour
We can then potentially zero in on a solution. Thanks!