Maximise does what it's name implies: Maximise. Try to maximise a window in Windows by pressing that button in the top right corner, and without covering the whole screen.
You will be bound by specific coordinates and sizes (especially the Width and Height cannot be made variable). I'm assuming that you want to let your chart expand to fill a specific reqion of the current screen space for different users and their multitude of monitor sizes. That will be difficult if not impossible (BTW that's a long running gripe that is handled by Qlik Sense if I'm not mistaken), even with a macro, since to my knowledge there is no way to obtain the current size of the client area.
Maximizing through chart will not help.create a copy of chart.One in default position and one in required maximized size. Mark layout->layer->top on to later one. positions the two charts correctly.
Now create a button that will conditionally show one of the two identical charts. also change text of button accordingly to maximize/minimize.
you can customize more by creating two buttons with static text minimize and maximize and place these buttons over chart at correct positions.
