- * Left-clicking on an uncovered tile: first we check to see if
- * the number of mine markers surrounding the tile is equal to
- * its mine count, and if so then we open all other surrounding
- * squares.
+ * Left-clicking or middle-clicking on an uncovered tile:
+ * first we check to see if the number of mine markers
+ * surrounding the tile is equal to its mine count, and if
+ * so then we open all other surrounding squares.