nsIMsgDBViewCommandUpdater interface controls changes that occur as the selection changes.
In Thunderbird this is implemented for different windows in several different places:
Called when the number of selected items changes.
Called when the displayed message has changed.
void displayMessageChanged(in nsIMsgFolder aFolder, in AString aSubject, in ACString aKeywords );
- The folder containing selected message.
- The subject of the selected message.
- Keywords associated with the selected message.
Allows the backend to tell the front end to re-determine which message we should select after a delete or move