On Plasma 4 you were able to middle click a running application on the "Icon's Only Task Manager" to launch a new application instance. However, on Plasma 5 you just can't launch a new application instance that way. You either have to right click the icon and choose "Start new instance" or you can press Shift + Left click. 

In fact, the option to use Shift + Left click was only added after this bug was fixed: https://bugs.kde.org/show_bug.cgi?id=340165

Someone suggested to (re)add middle click as an option aswell, however it was dismissed by a developer as that being an unintended use of the middle click button (see https://bugs.kde.org/show_bug.cgi?id=340165#c3). However, I disagree with this. There are already situations in which middle clicking is used to launch new "things" and not just to close "things". For example, on Chrome and Firefox middle clicking a link or a bookmark launches it on a new tab.

So, could you please add the possibility of middle clicking to launch a new instance? Or at least make it an option that we users can enable.

Reproducible: Always

Steps to Reproduce:
1. Open an application
2. Middle click its icon on the task manager

Actual Results:  
Nothing happens, or if you have something on the clipboard a note is added to the panel (very annoying behaviour by the way)

Expected Results:  
A new application instance should be launched

I'm running Kubuntu 15.04 Vivid Vervet with KDE Plasma 5.2.2