Do I Have a Gremlin Controlling My Browser

[#1]

Seriously have never experienced this problem before....
When browsing and I open a page directly from bookmarks or indirectly from hyper link or Google
the browser deselects it's self, yet I have no other program open or running.
The reason for the Gremlin is that I have attempted twice (with admin tools/task manager open) to
recreate situation, following identical paths. But of course it does not occur.
What's going on? 

[#2]

What do you mean by 'deselect' ?
Do you mean its no longer the default program for opening web pages? It closes itself down? What?

[#3]

I think maybe he means the browser window looses focus.

[#4]

Sorry could not remember correct term....
The open browser window is no longer the default running application.
It is only a niggle as to make it the default running application I just have to click within window....
Just that earlier I did so and clicked on an ad without realising had to shut down as ad had multiple opening windows.