ginput and modifier detection

Hi!

i would like to use ginput to select a position from an axis and then, according to the modifier used (CTRL or SHIFT) perform different actions.

i already assigned different actions depending on the mouse button pressed (1-2-3).

using this sintax:

    [x, y, button]=ginput(1)

the problem i face is that the value of the button variable resulting from a left click plus a modifier is the same as a right-click (CTRL+l-click) or middle-click (SHIFT+l-click).

Is there a way to detect which modifier was pressed?

Thank you