I think I found it, I was in "Quick measure: free " mode, it is the options above for quick measure tools.
when I selected Quick Measure: vertical I got what I wanted.
Do we have the same for Horizontal?
Do we have "quick measure: vertical" for the persistence view? we just have "quick measure: free"
If i use x cursors and y cursors yes i get as same as yours , but if i double click its as above , where as in 3.18.1 version i used get as original post.
version i am using is 3.21.16
How can we get vertical lines for cursors in a new version like the above - this was in the 3.18.1 version.
In the new version i get only horizontal line , its useful to align with the falling edge.