This is a odd "bug" (I don't consider it a feature). It is possible to move icons of active programs from the task manager to a other areas of the screen. This has the annoying side effect that sometimes the active program is brought into moving mode and it's impossible to properly get rid of it. If it is dropped into Firefox all that comes up is a random Chinese letters.  I have not found an option to disable this behaviour in the Task manager.

Reproducible: Always

Steps to Reproduce:
1. Log into KDE Plasma 5.8.2. Click on active program and move the icon of the active program.
2. Go to task manger and move the icon.
3.

Actual Results:  
Active programs can be moved to areas outside of the Task manager. This should not happen (according to the settings menu).

Expected Results:  
It should not be able to move the icons around outside the task manager.

The chinease text that shows up when Firefox icon (I've also tested this using the Shell window, shows the same information).

"楦敬⼺⼯獵⽲桳牡⽥灡汰捩瑡潩獮漯杲欮敤欮湯潳敬搮獥瑫灯਍"

Google translate says, "Last King ⼺ ⼯ Zongyang Qiang Tang Shan Yak ⸯ inertia destination time Ben Mu Lan ⽥ eliminating Transition Shiyi Hunting is the thing Han Yan Li Jiaotao lamp ਍"