There are some aspects of the Rigol DHO800 that I like and use all the time, like displaying multiple windows, for which the HDMI output to a bigger screen makes a lot of sense. Its XY functionality is also well featured, and the scope fan is not as loud. While the update rate of the FFT is relatively fast, its features could be vastly improved, and I am still hoping that Rigol will see the light and invest the few hours of development work needed to bring it up to par with the competition. (In the meantime, thanks in part to its fast update rate, it is quite easy (but far from ideal of course!) to quickly fetch FFT sample traces with a PC for further processing.)
That looks great! The combination of dockable windows and HDMI output to a larger screen was a part of my decision. I'm really looking forward to it after seeing those screenshots.
Just so you know:
Make note that window titles are scrambled and partial.
Going to a bigger screen won't give you better resolution, it will rescale current screen. It won't behave like you would expect if you connect second screen on a PC.
What you see on these screenshots is exactly how it will look, just bigger.
If that is what you expect than fine.
As for fixing FFT, it has been in this half cooked state for years now and I wouldn't hold my breath. Nor for any other fixes, to that matters. They sometimes fix some things, but priority and timing seems stochastic. And they take they sweet time.
But sometimes bugs are in parts of software you don't use so it doesn't matter. Sometimes for bugs to show it takes particular workflow so some people have crashes all the time and some almost never.
You will see and decide for yourself.