Notification Panel Motion tab redraws every ~30 seconds and loses scroll position

Hi Nx Support,

I'd like to report a long-standing problem with the Motion tab in the Notification Panel of the Nx Witness desktop client.

What happens:
- About every 30 seconds, all the thumbnail tiles in the Motion tab are visibly redrawn. This happens even when no new motion events have come in, whether the camera is showing live video or playback is paused.
- The lazy loaded thumbnails appear to be re-fetched from the server on each redraw rather than reused from a cache. They are sometimes slow to reappear, leaving tiles blank for a moment.
- After a redraw, the scroll position often jumps, in either direction. If I'm at the top viewing the most recent events, the list may scroll down. If I've scrolled down, it may jump back up. Either way I lose my place while reviewing events.

How to reproduce:
1. Open the Notification Panel and select the Motion tab.
2. Select a camera (in my case "Garage/back") and any time filter. It happens with every time filter I've tried.
3. Leave the list at the top, or scroll part way down, and leave it alone (live or paused makes no difference).
4. Within about 30 seconds the tiles redraw, and the scroll position often changes.

What I expect: the tiles should only update when new events arrive, existing thumbnails should not be reloaded, and the list should stay where I left it (except for at the very top where I'm happy for it to follow the most recent).

My setup:
- Nx Witness Client 6.1.3.43301 (aae7bab53087), linux-x64 (latest release; also seen on 6.1.2.42921)
- Nx Witness Server 6.1.3.43301
- I've also seen this on Windows, so it doesn't appear to be platform- or release-specific.

Is there a setting or workaround to stop this behaviour as it is quite annoying?

Thanks