I’ve recently been plagued by having white boxes/blocks around the controls in my Google Maps on one of my sites when using the Google Maps v3 Shortcode plugin in WordPress.
This is a problem with my theme, and not with the plugin itself which is excellent. In essence it is to do with the way the transparent background of the GIF images that make up the controls are displayed – they aren’t being displayed as transparent.
To solve this, have a look at your CSS stylesheet for your WordPress theme, scroll down until you find the bit describing how images are displayed (it’ll be “img” of some kind but will vary from theme to theme). Insert this into the curly brackets somewhere:
Hey presto, your transparent backgrounds are transparent again and your white boxes have disappeared.