Enabling/Disabling & Selecting Your Style
To enable or disable this item you’ll want to browse to Appearance > Customize > Header > Menu Search where you will a dropdown for your menu search style. Select the disable option to remove it:
Diamond includes a few search styles, not only so you can choose the one you like best but also because certain styles work better with different menu types and theme skins.
The drop-down style is the default style and will display a small search similar to your drop-down items.
Header replace will replace your header logo and navigation with a massive searchbar which is really trendy these days.
The overlay style is a more unique and it displays the searchform as a “pop-up”.
By default Diamond uses a different output for search results due to all the different post types to prevent conflicts as well as to keep the search results “slimmer”, however, if you want you can display your search results so they look just like your blog entries you can. Simply go to Appearance > Customize > General Theme Options > Search and select under “Style” the option “Inherit from Blog”.
Simply log into WordPress and go to Appearance > Customize > General Theme Options > Sidebar and here you can select the “No Sidebar” layout for your search results.