the refresh is currently needed for not only this one bug, but other bugs as well. The Segmentation editor JS was not implemented in a modern way and segment listing is buggy without the page reload after a change to segments.
Later sometime we'll rewrite the Segment Editor in AngularJS later so this reload will not be needed and the segment editor will be responsive and easy to use on mobile.
part of https://github.com/piwik/piwik/commit/0c9c30b731ccbacf47e154b9f7a590af49e3d799
I wouldn't say anything if it was only when adding or deleting, but this is also when switching a segment and this hugely decreases the usability and performance etc.
Yes definitely agree... will try to work on this later today https://github.com/piwik/piwik/issues/10972