[mu4e] Update mu4e only when appropriate

Trigger mail update only when the server is the one currently
active (the one associated to the running activity)

global.org

@@ -764,6 +764,13 @@
      ;; define 'z' as the shortcut
      (add-to-list 'mu4e-view-actions
                   '("zCreate agenda item for meeting" . create-item-for-meeting) t)
+     (advice-add 'mu4e-update-mail-and-index :around
+                 (lambda (orig-fun &rest args)
+                   "Only trigger an update if the server is the one that should
+     currently be active; otherwise each mu4e instance will trigger an
+     update"
+                   (when (string-equal server-name (kde-current-activity-name))
+                     (apply orig-fun args))))
 
      (advice-add 'mu4e~header-line-format :around
                  (lambda (orig-fun &rest args)