Strange screen

[marnav1]

Hello all.
Several times lately when I log on I get a screen with the title lightdm-webkit-greeter.
There doesn't seem to be any way to click out of it, there is no X on the top right or maybe its off the screen but I cant see an X. I have to restart to get rid of it.
Is there a way to disable this page or is it some kind of error ? Thanks ahead of time.

[marnav1]

Anyone ?

[Valtam]

Please search the Forums marnav1, this has already been covered. Thank you.