This is not a bug just for v9.5 as it is not a bug just under Windows 7. Previous versions of DOpus have this problem too and I have experienced it under WinXP Pro many times. In my experience, this bug is appeared (some times, not always) just when a script is applied to a file/files when preview modes is on. After some checking and unchecking Script mode option, the problem will be solved for a medium time.
This bug is very very similar with the bug that was mentioned in this topic (I cannot see any different between them, except the occurrence of Sasa's bug is appeared in a less degree and is not associated with a specific resolution).