As you can see Siglent only decodes and lists what is on-screen.
It can decode only what is captured. I do not know any scope what can decode things what are not captured.
And, what is captured is also on the screen. Siglent, unlike some others, show all what is captured on the screen and there is not captured part of trace outside of screen.
It looks like this is very hard to understand by peoples who have adapted to thinking that captured waveform length is over display width. Siglent use WICIWYS principle. There is is not unvisible part of captured waveform behind left or right diplay border, whole lenght of captured waveform is visible. This is also important for reduce blind time. All time what is not visible on the screen is time when user is blind for what is going on. Many scopes hide part of captured lenght and display is only narrow "slice" from whole capture lenght - just for nothing.
There is NOTHING out from window left or right border - repeat, there is nothing out from window what oscilloscope know, so it also can not decode this nothing. So why this nonsense question after every corner.
But about my old image quoted here. I do not know if zoom window and decoded byte counter (column: NO) in list is repaired. As can see time in the list is correct (column: TIME). And it decode just perfect when there is string before zoomed window left border. As can see zoomed window is in this example positioned to end of whole decoded string. Before original time of this image there was FW version where this did not work.