When text appears in the status field for items in the Since Last Run dialog (Ignored, Postponed, To-Create and Reminder), it's not obvious the text is clickable to bring up a menu. Some sort of decoration, such as button edges and/or a triangle to the left of the text, might cue the user that the status is changeable. Other information:
Created attachment 373260 [details] status-no-editable-indication.png Reproduces also in GnuCash 3.5 Attached screenshot
Added a second cell renderer to display image 'pan-down-symbolic' for the status column and will be in the next nightly or version 4.3