Dashboard flickering due to unexpected disappear/re-appear of original one-line src code at the top

[uboats]

In gdb + dashboard, when I stepped over the code, sometimes, the dashboard screen would be flickering. The reason seems to be the random appearance/disappearance of original gdb one-line source code display at the top of terminal window.

──────────────────────────────────────── ### here is top of terminal window (but you can still scroll up to see duplicated breakpoints/variables sections
1200 printf(xxxxxx) ### random disappear then re-appear during step over, and then below Threads section moves up and down looks like the screen is flickering
─── Threads ─────────────────────────────────
[2] xxxxxx
[1] xxxxx
─── Stack ───────────────────────────────────
....
...

Also, although terminal window is fully filled with selected sections (dashboard -layout threads stack breakpoints source variables history), the vertical scroll is still there. If I scroll up to end, I can only see duplicated history/breakpoints/variables sections (see below) with error messages. Not sure whether this is related to the flickering issue.

─── Breakpoints ──────────────────────────────────────
Traceback (most recent call last):
File "", line 558, in render
File "", line 2340, in lines
File "", line 290, in format_address
error: Selected thread is running.
─── Source ─────────────────────────────────────────
─── Variables ─────────────────────────────────────────
Traceback (most recent call last):
File "", line 558, in render
File "", line 1632, in lines
error: No frame is currently selected.