duplicate search field appearing with just one block
It's probably a css problem. 

My guess is the search bar is using a background image. The image contains both the inactive search background and the active search background. It's a good thing to avoid to load 2 different images.
If you want this to work, you need to ensure that the search box has a fixed height.

So in the css, you should have something like :

#edit-search-block-form--2 {
  height: 10px;   /* 10px =&gt; replace this with the real height */
}