Opened session

[Leon Pollak]

Almost each second time starting the kdevelop4 I receive:
The selected session is already active in another running instance

And, actually I do not know what to do with this...:-(
Sessions menu shows, that my session is the first, while "active" one is 
called "(no project)".
I cannot close it - it closes the kdevelop. I cannot switch to my actuall 
session - it says it is already active...

Any help will be highly appreciated. Together with a link to "what is the 
session" and how to deal with it...

Thanks a lot ahead.
-- 
leon