OK I have reproduced this problem now.Looking over the posts it hinted that the display was frozen until a button on the Quad was pressed.
By doing a quick test with the internal signal generator of course you don’t really see this as you have to push a button to get the signal generator to do something different and that itself triggers a refresh.
By using an external signal I do see that on the 200uSec range full screen there is a problem. Most of the time the signal does not retrigger and refresh until a scope button is pushed. If I increase the amplitude of the signal then it does cause a refresh as it passes through various levels. If I then decrease the signal then it doesn’t seem to trigger refreshes in the same way until the amplitude is quite small and then the display starts refreshing continuously.
I am not one of the developers of the application but I’d guess that there may be some sort of timing problem with the triggering getting re-armed at the right trigger level. Maybe there is some sort of time window where the re-arm is not done right and this window only occurs at this time-base and with full-screen display. Changing the buffering from full to single screen mode doesn’t seem to change behaviour which is a little odd as one would have expected that to change when the trigger gets re-armed.
Any developer watching who could comment? If not then I’ll try to have a look at the code in a few days when I have a bit more time.