Bug 1497544 - Use popup.xml#panel instead of popup.xml#tooltip for the IMTooltip after the tooltip binding removal. r=mkmelin

chat/content/imtooltip.xml

@@ -10,7 +10,7 @@
           xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
           xmlns:xbl="http://www.mozilla.org/xbl">
 
-  <binding id="tooltip" extends="chrome://global/content/bindings/popup.xml#tooltip">
+  <binding id="tooltip" extends="chrome://global/content/bindings/popup.xml#panel">
     <content noautohide="true" orient="vertical">
       <children>
         <xul:label class="tooltip-label" xbl:inherits="xbl:text=label" flex="1"/>

chat/themes/imtooltip.css

@@ -2,6 +2,10 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#imTooltip {
+  -moz-appearance: tooltip;
+}
+
 .displayNameMessageBox {
   margin-left: 4px;
   margin-top: 2px;