When you click on the currently active task in task bar, it minimizes the currently active task and activates the previously active task. It is the default Windows behaviour, and although some might find it useful to quickly swap between 2 tasks, just by clicking the same task button, I find this behaviour rather unintuitive (who would expect that an already open door would close when you try to open it again).
Precisely with many very similar tasks on the bar (ex. several notepads on similar files), when it is not always clear which one is active: you click the task you want to work with, but since it already was active, you in fact activate the previous one without noticing it, and start working on it unwittingly.
It would be easier if click on already active task kept this task active.
Could it be possible to have an option: "left click on active task keeps it active"
Customer support service by UserEcho