Stabilize order when merging overlapping screens.
Stabilize order when merging overlapping screens.

The order of overlapping screens is now defined by the
first screen in the merged set.

neg-serg/notion,dkogan/notion.xfttest,anoduck/notion,raboof/notion,raboof/notion,neg-serg/notion,p5n/notion,dkogan/notion,dkogan/notion.xfttest,knixeur/notion,dkogan/notion.xfttest,dkogan/notion.xfttest,raboof/notion,knixeur/notion,knixeur/notion,anoduck/notion,p5n/notion,dkogan/notion,raboof/notion,anoduck/notion,knixeur/notion,dkogan/notion,p5n/notion,p5n/notion,dkogan/notion,anoduck/notion,neg-serg/notion,p5n/notion,knixeur/notion,neg-serg/notion,dkogan/notion,anoduck/notion