Add an 'open' class to opened menus.

Never hide opened menus in the catalog.

css/style.css

@@ -447,8 +447,8 @@ a[href="javascript:;"] {
   margin: 0;
   vertical-align: text-top;
 }
-.thumb:not(:hover) > .menu-button > i {
-  visibility: hidden;
+.thumb:not(:hover) > .menu-button:not(.open) > i {
+  display: none;
 }
 .thumb > .menu-button {
   position: absolute;

src/General/UI.coffee

@@ -47,6 +47,7 @@ UI = do ->
       menu = @makeMenu()
       currentMenu       = menu
       lastToggledButton = button
+      $.addClass button, 'open'
 
       for entry in @entries
         @insertEntry entry, menu, data
@@ -99,6 +100,7 @@ UI = do ->
 
     close: =>
       $.rm currentMenu
+      $.rmClass lastToggledButton, 'open'
       currentMenu       = null
       lastToggledButton = null
       $.off d, 'click CloseMenu', @close