We have seen this for certain graphics card drivers.
One way of fixing it maybe to upgrade to the latest graphics card driver.
Alternatively one can disable Hardware Acceleration:
- Tools -> Options
- Uncheck “Enable Hardware Acceleration”
Also submitting a problem report from the machine doing this would be useful, with a description ‘all windows black’, (before upgrading graphics driver) as we could then record the problematic driver version number and blacklist it.