In the latest release of DxDesigner we introduce an enhanced lined grid. If you are using custom color schemes it is likely that your grid will need adjusting for this new style. This can be done by making chnages in the color schemes either by using the UI or directly in the *.dxc files. The delivered colored schemes have been adjusted already and here are some suggestions for tweaking your own schemes.
For white backgrounds
<item name="GRID" color="0xb2b2b2"/>
For black backgrounds
<item name="GRID" color="0x484848"/>
If you wish to continue to use the dot grid then the delivered color schemes will need adjusting in the oposite direction.
P.S. For highlights in the 7.9.4 release see this video on SupportNet