Some people have experienced a situation when a PowerPoint is run that the output display is at a resolution that doesn't match the ZionWorx presenter window. This mis-resolution also has a flow on effect to other items that are shown through ZionWorx.
This problem is actually caused by a setting in PowerPoint itself where you can specify an output resolution that is used regardless of what the output display is actually set at. You can actually see when the PowerPoint is run a flicker in the displays as the resolutions are set and this can be reproduced when running the PowerPoint outside of ZionWorx.
The resolution is quite straight-forward. In PowerPoint (you will probably need to have a presentation open to change the setting) find the output resolution setting and change to be "Use Current Resolution". Different PowerPoint versions have this setting in different places. Two common locations are pictured below.
NOTE - It is also helpful to untick the Use Presenter View option in PowerPoint as well as this can sometimes cause conflicts.