Once multiple instances of some task (e.g. Iceweasel, QtCreator) are running, they get stacked into one taskbar item, what is perfect. However recently the stack indicator overlapping the original task icon changed from very small and not disturbing triangle at the left of that item to the large, even thick white bordered triangle, which completely occludes  the task icon.
As I use to have more than one stacked item routinely and select them visually by the task icon, I would like you (or themes designer policy) to either return to previous indicator design (small, non-disturbing) or to move indicator out of the task icon position (probably rightmost of task "button" would be good place instead of leftmost (icon) position).

Reproducible: Always

Steps to Reproduce:
1.Make some type of task stacked in taskbar.
2.
3.

Actual Results:  
Task type icon occluded.

Expected Results:  
Task type icon visible.