Version:           unspecified (using KDE 4.7.0) 
OS:                Linux

I am using different virtual desktops, here are the two incriminated :
One with my Firefox (Web Browser) in virtual desktop no. 1
One with Konversation (IRC client) in virtual desktop no. 2

When I click, in Konversation in virtual desktop no. 2, it's gonna proceed to open a new tab in my Firefox in virtual desktop no. 1.

HOWEVER, it's showing a new tab in the taskbar (in virtual desktop no. 2) to say it's opening Firefox and the mouse cursor also got the Firefox icon for 20 or more seconds, as if it were still starting.

After opening a few links, the taskbar gets filled of "ghost tabs" pushing the new tabs on the right to the maximum. You can see that in the attachment.

Reproducible: Always

Steps to Reproduce:
Open an application in a virtual desktop, and another calling the first one in a second virtual desktop.
In the second application, make the call to the first one (ex.: click on a web link to call a web browser opened in another virtual desktop)

Actual Results:  
The taskbar is getting filled of "ghost tabs" and is still displaying the tab for launching the application. See attachment

Expected Results:  
Remove the ghost tabs and free the taskbar.