Bug 1930588 - Set agenda selection on modification only when the item was already selected. r=mkmelin

Differential Revision: https://phabricator.services.mozilla.com/D228626

--HG--
extra : rebase_source : 168230b9996d35ebc78aaacc88ea80ccacddea93
extra : amend_source : 96cb1fbb983f84a2ae404c6e24109ee02e5ec173

calendar/base/content/today-pane-agenda.js

@@ -85,6 +85,8 @@
         while (this.lastChild) {
           this.lastChild.remove();
         }
+
+        delete this._lastRemovedID;
       }
 
       /**
@@ -108,6 +110,8 @@
             setTimeout(() => (this.selectedIndex = this.rows.indexOf(startItem)));
           }
         }
+
+        delete this._lastRemovedID;
       }
 
       /**
@@ -116,6 +120,8 @@
        * @param {calIItemBase[]} items
        */
       removeItems(items) {
+        delete this._lastRemovedID;
+
         for (const item of items) {
           const startItem = document.getElementById(`agenda-listitem-${item.hashId}`);
           if (!startItem) {
@@ -124,7 +130,9 @@
           }
 
           this.removeListItem(startItem);
-          this._lastRemovedID = startItem.id;
+          if (this.selectedRow == startItem) {
+            this._lastRemovedID = startItem.id;
+          }
         }
       }
 
@@ -142,6 +150,8 @@
             li.remove();
           }
         }
+
+        delete this._lastRemovedID;
       }
 
       /**