Text cursor in fake vim mode in Qt Creator

[Guest]

I would like to know how the text cursor in fake vim mode was implemented and more precisely how it is made to be transparent over
text. In the example below, this situation is when the cursor is over {. I tried to find that in the source code but without success.

"This is example":http://www.google.com/imgres?um=1&hl=en&sa=N&tbo=d&biw=1301&bih=656&tbm=isch&tbnid=rLbztQJ68betzM:&imgrefurl=http://nightsailer.com/2009/02/08/374.html/fakevim&docid=iY8VEFhC0zAW7M&itg=1&imgurl=http://nightsailer.com/wp-content/uploads/2009/02/fakevim.png&w=1028&h=393&ei=rbC9UNf3KOyZ0QWKvIBA&zoom=1&iact=hc&vpx=899&vpy=177&dur=1651&hovh=139&hovw=363&tx=189&ty=70&sig=109861259623703771343&page=2&tbnh=103&tbnw=268&start=24&ndsp=25&ved=1t:429,r:29,s:0,i:180