The intended behavior should work as follows:

1. When the user clicks an icon of an application that is not focused, the Task Manager should change to the last active window of the application (whether the application has one or more windows).

2. Since the left click will no longer show the list of the application windows, when the user right clicks on an application icon, the context menu should also display the list of windows of the application (if there are any).

I tried to do both things by editing the Task Manager QML files but only got item 2 working. You can see what I've done here: https://github.com/gmsanchez/plasma_taskmanager/