id summary reporter owner description type status priority milestone component version resolution keywords cc 13250 [Patch] JOSM seems to hang after sorting members of a complex relation GerdP team "Select a multipolygon relation with > 6000 members, e.g. 6040654 Edit the relation Click on the sort members icon After a short time (maybe 4 seconds) all members are marked as changed but JOSM doesn't respond for minutes (no idea how long it will take) The time is consumed in a loop that invokes boolean org.openstreetmap.josm.gui.util.HighlightHelper.highlightOnly(Collection prims) with an Arraylist, and for this List the contains() method is called. If I got that right, this is repeated for each member, and the list is growing with each member, so after some iterations you have a sequential search on thousands of elements, repeated for thousands of times. Using a Hashset instead of an ArrayList improves performance heavily, but maybe the problem could be solved better elsewhere. Attached is a patch that shows where to use the HashSet. " enhancement closed normal 16.07 Core fixed Performance Relation Editor