Well, it's not easy to explain...
Like this; I'm writing text in Notepad:
I_______________________________I
I_Hello, my name is Arvid__________I
I_______________________________I
I_______________________________I
I_______________________________I
And then after (I think) pressing a bit on the Ctrl and arrow-keys, to move the marker around in the text, it suddenly turns into this:
I_______________________________I
I__________Hello, my name is Arvid_I
I_______________________________I
I_______________________________I
I_______________________________I
And sometimes the keys change too at the same time, so if I press on the left arrow key, the marker moves to the right...