I downloaded NirLauncher 1.17.18.   It downloads as a Zip file.  The Zip file contains a bunch of utilities from NirSoft.   I ran a BD W8 Security contextual scan by right clicking the Zip file locating the Bitdender line item in Windows Explorer.   The scan identified a number of items as malicious.   I chose to Cancel or clicked on the "x" on the top right of the GUI.  I can't remember which.   Whether I should have let Bitdefender take an action rather than clicking on Cancel or closing the GUI is besides the point here.  That was my choice.  I then deleted the Zip file and cleaned the Recycle bin.
I then right clicked on an executable file and the line item for the BD W8 Security contextual scan in Windows Explorer was gone.   I retarted W8 and it returned.
The point of all of this is not whether I should have let BD W8 Security complete the operation of quarantining or deleting the items it found as being malicious.
The point is that when I cancelled the scan or closed the GUI by clicking on the "X" the option to run the BD W8 Security contexctual scan from Windows Explorer was no longer available.    I did open Bitdefender and the main GUI indicated everything was okay.    This should be looked at by Bitdefender to see if they can duplicate.
Thanks for reading