dual monitor refresh issue (jerky screens)

Hi everybody

Users complain that with a dual screen mode the screen stutters. Sometimes the second screen is frozen.  Only if you change with the mouse to the second screen, the content (windows, icons etc.) is rebuilt.
We use vWorkspace with ThinOS 8.6_19. The models are 3030lt and 5010. All models have the problem. Depending on the equipment, the monitors (Samsung S24E60) are connected via DP or DVI. It makes no difference.
We had similar problems with 8.6_013. It was a bit better with 8.5_xx
The resolution of the monitors is 1920×1200 at 60hz. This corresponds to the setting suggested by Samsung. I’ve already changed monitor cables and monitors without success.
Monitor Display Settings
Enable Dual Monitor Yes Development
Dual Monitor Mode Span Mode Development
Main Screen Screen 1 Development
Alignment Bottom Development
Layout (8.5+) Landscape Development
Taskbar (8.5+) Development
Auto detect monitors (8.5+) Yes Development
Desktop Color Depth 32-bit development
Primary Monitor Settings
Monitor Resolution DDC Development
Monitor Rotation None Development
Secondary Monitor Settings
Monitor Resolution (8.5+) DDC Development
Monitor Rotation (8.5+) None Development
Multi-Touch (8.6+)
Multi-touch No Development
Screen Saver Settings
Screensaver (8.5+) 0 Development
Lock the terminal (8.5+) 1 Development
Screen Saver Type (8.5+) Development
Sleep (8.5+) 10 Development
Use Hours instead of Minutes (8.6+) No
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