MDL-37162: Use CSS to make mod show/hide icons not look "clickable" in hidden sections

Previously, the resource toolbox initialiser was using JS to find the show/hide icon, then find its section ancestor, then check if the section was hidden - only to pointlessly set pointer:auto if it was.  That didn't meet the aim stated in the comments ("Disable" show/hide icons (change cursor to not look clickable) if section is hidden), but this patch meets that goal with a single CSS rule.

course/yui/toolboxes/toolboxes.js

@@ -259,15 +259,6 @@ YUI.add('moodle-course-toolboxes', function(Y) {
         },
         _setup_for_resource : function(toolboxtarget) {
             toolboxtarget = Y.one(toolboxtarget);
-            // "Disable" show/hide icons (change cursor to not look clickable) if section is hidden
-            var showhide = toolboxtarget.all(CSS.COMMANDSPAN + ' ' + CSS.HIDE);
-            showhide.concat(toolboxtarget.all(CSS.COMMANDSPAN + ' ' + CSS.SHOW));
-            showhide.each(function(node) {
-                var section = node.ancestor(CSS.SECTIONLI);
-                if (section && section.hasClass(CSS.SECTIONHIDDENCLASS)) {
-                    node.setStyle('cursor', 'auto');
-                }
-            });
 
             // Set groupmode attribute for use by this.toggle_groupmode()
             var groups;
@@ -708,12 +699,6 @@ YUI.add('moodle-course-toolboxes', function(Y) {
                 if (Y.Array.indexOf(response.resourcestotoggle, activityid) != -1) {
                     this.toggle_hide_resource_ui(button);
                 }
-
-                if (value == 0) {
-                    button.setStyle('cursor', 'auto');
-                } else {
-                    button.setStyle('cursor', 'pointer');
-                }
             }, this);
         },
         toggle_highlight : function(e) {

theme/base/style/course.css

@@ -87,6 +87,9 @@
 .dir-rtl.path-course-view .completionprogress {float: none;}
 .dir-rtl.path-course-view li.activity form.togglecompletion .ajaxworking {right: -22px;}
 
+li.section.hidden span.commands a.editing_hide,
+li.section.hidden span.commands a.editing_show {cursor:default;}
+
 .section img.movetarget {height:16px;width:80px;}
 
 #page-course-enrol .generalbox,