I have seen this same issue for IE11 and Robohelp 11. I did not see a resolution.
It seems that I am experiencing the same issue. Any help is appreciated.
In IE11 the help opens, but there is an additional small blank window that also it opens along with it, It does not display in the main screen, but when you close the help window then that small window displays in the main screen then the user has to manually close it. This is not an issue in IE10.