This event consists of a single serialized map containing a property
+change (string)+ which indicates the type of the change ("focus", "init",
-"empty", "urgent"). Additionally, when the change is "focus", an +old
-(object)+ and a +current (object)+ properties will be present with the
-previous and current workspace respectively. When the first switch
-occurs (when i3 focuses the workspace visible at the beginning) there is
-no previous workspace, and the +old+ property will be set to +null+.
+"empty", "urgent").
+
+Moreover, when the change is "focus", an +old (object)+ and a +current
+(object)+ properties will be present with the previous and current
+workspace respectively. When the first switch occurs (when i3 focuses
+the workspace visible at the beginning) there is no previous
+workspace, and the +old+ property will be set to +null+. Also note
+that if the previous is empty it will get destroyed when switching,
+but will still be present in the "old" property.
*Example:*
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