Corel 18 Tiling.---- Does not tile like previous versions......a big problem

I started using upgrade Corel 18 recently. Multiple windows do not work the same as 16 or before. It is a problem when viewing as tiled. Example if you have six or how many windows open, only three windows will tile. One needs to tile manually, but it will not retile correctly after that. In 16 and previous versions all six or how many windows show when tiled.

Also, if you cascade windows you can not tile again through the drop down menu. 

This is a huge problem when working production, or needing multiple windows.

Is there a fix??