Mouse-over for buildings in planet view

[icydee]

Mouse-over on planet view shows either a pointer (clickable) or hand (draggable) depending upon where you hover.

It is expected that you can click anywhere in the square to bring up the building panel.
In practice, if the draggable pointer is showing a click does not work.
On lacuna-1, the click works correctly.

Work-around, ensure that the pointer is showing (central area over the 'level' number) before clicking.