After last Windows 7 update (KB4034664) in the multi monitor environment spark working only on the first screen. If spark moved to the another screen - stops redraw program window. If move back on the first screen - working ok.
I have tried on Windows 7 x86 with two monitors (laptop + external one). Without or with this update it behaves correctly. Using default Luna skin. 2.8.3 version of Spark.
I have had the exact same issue. It does seem to work on the default monitor. I always use it on monitor 2. Thanks for the workaround.
This is a bug in a Microsoft Security Patch. See this blog entry for more details and a workaround:
Graphics Bug in Windows 7 after installing August 2017 Security Updates | Wolfsbeeren
A fix https://support.microsoft.com/en-us/help/4039884/windows-7-update-kb4039884
Thanks, I have 30 machines being 22 with two monitors, the problem was solved with this correction.