Bug #215901 --> formatting toolbar gets disabled in mail compose when selecting any drop down list. Port a missing style rule

over from classic\global.css

r=ben

toolkit/skin/win/global.css

@@ -156,3 +156,9 @@ sidebarheader {
 sidebarheader > label {
   padding-left: 4px;
 }
+
+/* ::::: miscellaneous ::::: */
+
+.toolbar-focustarget {
+  -moz-user-focus: ignore !important;
+}