Go to Layout mode, open Inspector>Appearance tab. Click once on button you want to change. On appearance tab at top you'll see a drop down list that says Normal State, with a drop-down arrow. Click that and select Hover. If the button turns gray you can fix it there.
Or if you can't figure out the settings, click a button that works properly. Click Appearance tab drop down to Hover. Right above drop down are 4 buttons. Click 'copy style'. Click back to button you need to change, click hover, click the button next to copy style which should be 'Paste a style....".