fix firefox flex bug in ticket zoom

app/assets/javascripts/app/views/ticket_zoom.jst.eco

@@ -1,5 +1,4 @@
-<div class="tabsSidebar-holder flex vertical">
-  <div class="flex u-positionOrigin horizontal">
+<div class="tabsSidebar-holder">
   <div class="main no-padding flex tabsSidebar-sidebarSpacer tabsSidebar-tabsSpacer">
     <div class="ticketZoom">
       <div class="scrollPageHeader tabsSidebar-sidebarSpacer zIndex-9 horizontal center"
@@ -51,7 +50,6 @@
   </div>
 
   <div class="tabsSidebar vertical"></div>
-  </div>
 
   <div class="attributeBar">
     <form class="form-inline is-closed hide" role="form">

app/assets/stylesheets/zammad.css.scss

@@ -3442,6 +3442,8 @@ footer {
 .tabsSidebar-holder {
   overflow: hidden;
   position: relative;
+  @extend .flex;
+  @extend .vertical;
 }
 
 .tabsSidebar .sidebar {
@@ -3500,7 +3502,7 @@ footer {
     position: absolute;
     right: 0;
     top: 0;
-    bottom: 0;
+    bottom: 60px;
     transition: 500ms;
   }
 
@@ -4799,6 +4801,14 @@ body.fit {
               flex: 1;
 }
 
+.flex-full {
+  -webkit-box-flex: 1;
+  -webkit-flex: 1 1 100%;
+     -moz-flex: 1 1 100%;
+      -ms-flex: 1 1 100%;
+          flex: 1 1 100%;
+}
+
 .flex-auto {
   -webkit-box-flex: 1;
   -webkit-flex: 1 1 auto;