If you want to see hover tips for all objects, verify you did not enable in the "Tools" menu the "Select only my/moving objects" options, and also un-tick the "Limit maximum selection distance to:" check box, or change the distance via the corresponding spinner to the limit you want, in the "Preferences" floater, "Input & camera" tab, "Input controls" sub-tab.

Note also that the object tips may take a couple seconds to load (a request for the object info is done to the server, when that info is not already cached, incurring a small delay).