We are going to implement this feature together with a few other features related to the address book and generally how the records are shown.
Currently, our major priority is making the user/permission management system more advanced and immediately after that we will most likely get down to implementing better address book viewing capabilities, including the search function. While we could quickly make at least some search function, this would go against our rules to make everything as well thought-out as possible :) While seemingly simple a good search function is no trivial task nonetheless.
You probably should enable the "Capture alpha-blending windows" in the connection properties. Right-click on the connection in your address book, click Properties -> Additional properties and tick the "Capture alpha-blending windows" check box.
Alpha-blending windows are semi-transparent windows and menus.