The icons that the taskbar creates when enabling "show a launcher when not running" are smaller than the other panel icons. They should be same size to match. I will attach a screenshot
Steps to Reproduce:
1.Drag an icon from the k-menu to the left of the taskbar
2.Right click a program in the task bar and click "show a launcher when not running".
3. Close the program and compare size of icons.
Created attachment 72601 [details]
Thanks for writing this, now I finally know where those small icons come from. They sometimes appear in the panel and stay but I never ticked anything like "show a launcher when not running". And yes they definitly are too small, they should adapt to the size of the other launchers.
*** Bug 297805 has been marked as a duplicate of this bug. ***
Confirmed with KDE 4.9.0
*** This bug has been marked as a duplicate of bug 302778 ***