Fixed issues with the find-replace menu

Fixed the opacity of the preserve case icon (the padlock), as well as the width of the replace button. 

Before
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![replace-before](https://f.cloud.github.com/assets/2287437/405862/8850131a-aa1b-11e2-9686-11410157cb34.png)

After
======
![replace-after](https://f.cloud.github.com/assets/2287437/405864/90eb1df8-aa1b-11e2-934d-586d02e8c27e.png)