I hope to help who will face my same issue.
I've upgraded to QV 11 and reload the documents created by QV 10. Before version 11 to limits the number of elements (for instance in a graph) it was sufficient provide that number on the dimension limits.
Now that setup has been moved to "Dimension Limit" option; my issue is that is calculated on the first expression value.
In my example I have a trend: days on x axes and sales on y axes. If I select "Dimension Limit" largest 10 I will have the 10 days with the biggest sales. If I select first 10 I will have the first 10 days with sales starting from the first day of sales.
My goal is to have the latest 10 days of sales. To do this I've created a new expression with the day value, deselected all the representations option (bar, symbol, line, etc) and selected "Invisible".
In this way my new expression is used only to lead my dimension limit. At this point selecting largest 10 I will have the latest 10 days of sales.
Hope to be helpful to someone,