Improved external rules and fixed inconsistent browser names

misc/bin/externalrules

@@ -5,6 +5,7 @@ wid=$1
 class=$2
 instance=$3
 consequences=$4
+title="$(xdotool getwindowname "$wid")"
 
 outcome() {
 	eval "$consequences"
@@ -28,3 +29,12 @@ case "$class" in
     outcome "state=floating rectangle=900x700+0+0 center=on"
     ;;
 esac
+
+case "$title" in
+  "Steam Settings")
+    outcome "state=floating center=on"
+    ;;
+  "Prism Launcher: Staff Client Modloader")
+    outcome "state=fullscreen"
+    ;;
+esac