fix for #56074. thanks to andrew taylor (andrew.taylor@cal.montage.ca) for the fix.

r=sspitzer,sr=bienvenu

mailnews/base/prefs/resources/content/AccountManager.js

@@ -235,7 +235,11 @@ function onDeleteAccount(event) {
     var type = server.type; 
 
     var protocolinfo = Components.classes["@mozilla.org/messenger/protocol/info;1?type=" + type].getService(Components.interfaces.nsIMsgProtocolInfo);
-    if (!protocolinfo.canDelete) return;
+    var canDelete = protocolinfo.canDelete;
+    if (!canDelete) {
+        canDelete = server.canDelete;
+    }
+    if (!canDelete) return;
 
     var confirmDeleteAccount =
       Bundle.GetStringFromName("confirmDeleteAccount");
@@ -329,8 +333,10 @@ function updateButtons(tree,serverId) {
 
 	var protocolinfo = Components.classes["@mozilla.org/messenger/protocol/info;1?type=" + type].getService(Components.interfaces.nsIMsgProtocolInfo);
     canDuplicate = protocolinfo.canDuplicate;
-	canDelete = protocolinfo.canDelete;
-
+    canDelete = protocolinfo.canDelete;
+    if (!canDelete) {
+      canDelete = server.canDelete;
+    }
   }
   else {
 	// HACK

mailnews/base/public/nsIMsgIncomingServer.idl

@@ -182,6 +182,13 @@ interface nsIMsgIncomingServer : nsISupports {
 
   /* used for comparing nsIMsgIncomingServers */
   boolean equals(in nsIMsgIncomingServer server);
+
+  /**
+   * can this server be removed from the account manager?  for
+   * instance, local mail is not removable, but an imported folder is 
+   */
+  attribute boolean canDelete;
+
 };
 
 %{C++

mailnews/base/util/nsMsgIncomingServer.cpp

@@ -1054,6 +1054,18 @@ nsMsgIncomingServer::getProtocolInfo(nsIMsgProtocolInfo **aResult)
     return NS_OK;
 }
 
+NS_IMETHODIMP nsMsgIncomingServer::GetCanDelete(PRBool* value)
+{
+    NS_ENSURE_ARG_POINTER(value);
+
+    return GetBoolValue("canDelete", value);
+}
+
+NS_IMETHODIMP nsMsgIncomingServer::SetCanDelete(PRBool value)
+{
+    return SetBoolValue("canDelete", value);
+}
+
 // use the convenience macros to implement the accessors
 NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, Username, "userName");
 NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, PrefPassword, "password");

mailnews/import/src/nsImportMail.cpp

@@ -1042,6 +1042,10 @@ PRBool nsImportGenericMail::GetAccount( nsIMsgFolder **ppFolder)
 	}
 	server->SetType( "none");
 
+    // usually, servers of type none can't be deleted; this must be
+    // overridden
+    server->SetCanDelete(PR_TRUE);
+
 	// Let's get a reasonable "pretty name" that doesn't exist yet?
 	GetUniquePrettyName( accMgr, prettyName);
 	

mailnews/mailnews.js

@@ -409,6 +409,7 @@ pref("mail.server.default.empty_trash_on_exit", false);
 
 pref("mail.server.default.using_subscription", true);
 pref("mail.server.default.dual_use_folders", true);
+pref("mail.server.default.canDelete", false);
 
 pref("mail.smtpserver.default.auth_method", 2); // auth login
 

modules/libpref/src/init/mailnews.js

@@ -409,6 +409,7 @@ pref("mail.server.default.empty_trash_on_exit", false);
 
 pref("mail.server.default.using_subscription", true);
 pref("mail.server.default.dual_use_folders", true);
+pref("mail.server.default.canDelete", false);
 
 pref("mail.smtpserver.default.auth_method", 2); // auth login