Using IE (IE7 in my case) navigate to the Resources->Search menu item. Type in something with a lot of resource hits (e.g. "ejb"). Anything that will generate horizontal or vertical scrolling. Try using the scroll bars. The result box goes away as if the scroll bars are outside the results area.
jshaughn -- is this the search bar or the smartgwt component?
Neither. This is reported against RHQ 3.0 and it's talking about the core menu item Resources->Search. This is the ajax-y search widget that generates a resource menu on the fly, given the typed in string. This should not be relevant to rhq4.
fixed in current release