Using the middle mouse button to select a cell that contains a hyperlink causes some unexpected behavior. Specifically, Shift-middle-click behaves like Control-left-click, selecting an additional range instead of extending the current range. Also, middle-click does not work within the current selection.

To duplicate the first problem, select a cell, then move to a non-adjacent cell, press and hold the Shift key, and middle-click. Both cells will be highlighted, as if they had been selected with Control-left-click, and any operation that can be applied to a discontinuous selection will apply to the highlighted cells. (Note that Control-middle-click behaves the same way, as it should if middle-click does not ignore the modifier keys.)

To duplicate the second problem, select more than one cell, then move to one of the selected cells and middle-click. The selection does not change, while left-click at the same point would change the selection to that single cell (assuming no hyperlink is present).