As shown in the figure, there are two split windows in the figure, and the one on the right appears when taglist is opened.
I specially added it
set nuFor comparison.
What is the gray vertical bar on the leftmost side of the taglist window and how to control it?
That is calledsign column, you can look inside vim to help you understand it in detail.
To get rid of it, I think the simplest way is:
:sign unplace *, give it a try.