I am testing the following change in 4.4-alpha:
ggg. The commands executed by `bind -x' now redisplay at most the final line
of a multi-line prompt, and those commands may return 124 to indicate that
the entire prompt should be redrawn.
This is great news and means that two-line prompts now can be used with "bind -x". It seems to work as intended.
I see that a function can return 124 to make the whole prompt redisplay. However, for my purposes, it would be even better if there also was a code that a function could return which would inhibit all redisplay of the prompt.
I have described the kind of "widget functions" that I use in the thread "bind -x and multiple prompt/command lines" from April of 2014. When using such a function, the flickering that results from the prompt redisplaying is a bit annoying.
If there were some return code that could inhibit the prompt redisplay, that would therefore be great.