Please help! My wall marker has disapeared!

[sagisen78]

Suddenly my wall marker dissapeared (in building mode). I can still put up walls but that thing that marks where the wall starts is lost.

I have all ep & pp except supernatural. Game is updated to the latest patch.

Please help me!
Thanks 

//Maria

[donatello]

I get it too sometimes. But only when my computer seems to be a bit slow because of doing whatever it does when it does it in the background. Or when it is about time for a save and the cache is close to full. It robs the resources needed to render some things, and I'm sure the game gives preference to actual buildings above building tool markers.