If there is a mine surrounded on all sides by other mines, you can not click on it... it's extra frustrating when it's the very last one. =) Otherwise fun game!
In the following example, it is impossible to click on the circled mine:
Bug selecting mine?
A bug indeed!
HexAddict is supposed to make sure that can never happen, but there's apparently a bug as you say. We'll look into it!
Leon
Leon