Checking in for Neil <neil@parkwaycc.co.uk>

Fix for bug 107829. Clear QuickSearch, must select msg/folder pane to use Next/navig button/shortcuts.
r=naving, sr=sspitzer, a=asa

mailnews/base/resources/content/mail3PaneWindowCommands.js

@@ -354,8 +354,9 @@ var DefaultController =
         return(MailAreaHasFocus() && GetNumSelectedMessages() > 0);
       case "cmd_editDraft":
                 return (gIsEditableMsgFolder && (GetNumSelectedMessages() > 0));
-      case "cmd_nextMsg":
       case "button_next":
+        return IsViewNavigationItemEnabled();
+      case "cmd_nextMsg":
       case "cmd_nextUnreadMsg":
       case "cmd_nextUnreadThread":
       case "cmd_previousMsg":
@@ -492,6 +493,7 @@ var DefaultController =
                 if (gDBView.numSelected >= 0)
                     MsgComposeDraftMessage();
 				break;
+      case "button_next":
 			case "cmd_nextUnreadMsg":
 				MsgNextUnreadMessage();
 				break;

mailnews/base/resources/content/mailWindowOverlay.xul

@@ -1463,7 +1463,7 @@ Rights Reserved.
         </template>
         <menupopup/>
       </toolbarbutton>
-      <toolbarbutton class="toolbarbutton-1" id="button-next" label="&nextButton.label;"  oncommand="goDoCommand('cmd_nextUnreadMsg')" tooltiptext="&nextButton.tooltip;" observes="button_next"/>
+      <toolbarbutton class="toolbarbutton-1" id="button-next" label="&nextButton.label;" oncommand="goDoCommand('button_next')" tooltiptext="&nextButton.tooltip;" observes="button_next"/>
       <toolbarbutton class="toolbarbutton-1" id="button-delete" label="&deleteButton.label;" tooltiptext="&deleteButton.tooltip;" observes="button_delete" oncommand="goDoCommand('button_delete')"/>
       <toolbarbutton type="menu-button" id="button-mark" class="toolbarbutton-1" label="&markButton.label;" hidden="true" oncommand="goDoCommand('button_mark')"
                   observes="button_mark" tooltiptext="&markButton.tooltip;">