There are 3 different options of left-clicking upon current active group: show previews, switch windows in cycle or open last window if group is not active.
I would suggest you to add additional option to hide/minimize current active window, when left-clicking its current active group. I think it is very comfortable when you can minimize window by clicking it on the taskbar, without moving your mouse to the top right corner of the window. It is also comfortable, when you want to quickly see some information in maximized window and then hide it in order to switch to other window. Please, consider such an option.
Customer support service by UserEcho