Blank laptop screen after disconnecting projector

[CS DBA]

All;

I recently installed Fedora21 (KDE Spin) on a new Dell M3800

Everything was working beautifully, one of the things I do on a regular 
basis is to rsync my hard drive (skipping the directories created at 
runtime) to a backup location

I have been connecting & disconnection the laptop to/from 2 separate 
monitors via the mini display port & a mini display port to vga adapter 
with no issues.

earlier tonite I did a presentation to a local users group meeting, all 
went fine, I plugged their projector into the mini display port and the 
presentation worked fine.

However when I unplugged the projector mu laptop screen went blank, I 
rebooted and logged into a blank screen, after a reboot I could plug the 
projector in again and get dual screens (laptop and projector screen), 
If I unplugged the projector I get a blank screen on the laptop again.

I restored a full backup rebooted, same problem... I'm now doing a full 
re-install of Fedora 21.  I'd like to avoid this in the future, any help 
would be much appreciated.

Thanks in advance