This problem occurs on some machines due to a deep bug in some windows graphics drivers.
Unfortunately, there is no direct solution.
Fortunately, there is an easy workaround - select "full screen mode" from the drop down box just below the question pane and work in full-screen mode. This works via a different drawing technology and thus will not be subject to this irregularity.
We provide customer and technical support via this online helpdesk. This allows you to receive prompt
(sometimes instant), efficient help from either our automated response system and/or the exact person who can best assist
you. As a plus, such a system ensures that a detailed written record of the conversation is available for you
which can be extremely helpful when asking for and receiving technical help.
While the vast, vast majority of our visitors understand and appreciate this industry-standard system, to some of you
such an online helpdesk may nevertheless be a new concept. If so, please click here
to learn more about why we do things this way. Thank you for your understanding!.