XWIKI-21864: Menu Application: If list element is a link, the xDropdo…

…wn-header-toggle drops to a new line and other weirdness (#2893)

* Fixed incorrect padding on link section headers in the submenus
* Positioned the toggle absolutely in those sections so that it doesn't eat away at space the text had before and force a linebreak where there used to be none.

xwiki-platform-core/xwiki-platform-menu/xwiki-platform-menu-ui/src/main/resources/Menu/MenuMacro.xml

@@ -853,10 +853,17 @@ require(['jquery','xwiki-l10n!menu-ui-translation-keys'], function($, l10n) {
               }
             }
             /* When in dropdown we also have a link, reset the duplicated padding */
-            & > span > a {
+            & > .xDropdown-header > span > a {
               padding: 0;
               display: inherit;
             }
+            /* Reposition the toggle when in a dropdown of fixed size
+              to avoid eating away at the bit of space we have for the text. */
+            & > .xDropdown-header > .xDropdown-header-toggle {
+              position: absolute;
+              right: 0;
+              top: 0;
+            }
           }
           /* Separator horizontal inside menu */
           &:empty {