When I move to a new level the cursor reverts to a simple arrow and does not turn into a green square to dig.

Clicking or right clicking does nothing.

I got round it on some levels by exiting the programme and then re-launching, but now I am at level 8 and no matter what i do, when I go in to start the level I cannot use the cursor.

I have tried the repair function but still no use.

Does anyone have any ideas?