MDL-42634 theme: Action menu is displayed correctly with hidden elements

theme/base/style/blocks.css

@@ -20,7 +20,10 @@
 .block.beingmoved {border-width: 2px;border-style: dashed;}
 .blockmovetarget {display: block;height: 1em;margin-bottom: 1em;border-width: 2px;border-style: dashed;}
 
-.block-region .invisible {opacity: 0.5;filter: alpha(opacity=50);}
+.block-region block.invisible .header h2 {
+    opacity: 0.5;
+    filter: alpha(opacity=50);
+}
 
 .block .block-hider-show,
 .block .block-hider-hide {cursor:pointer;}

theme/bootstrapbase/less/moodle/blocks.less

@@ -64,7 +64,9 @@
         border-style: dashed;
     }
     &.invisible {
-        .opacity(50);
+        .header h2 {
+            .opacity(50);
+        }
     }
 
     &.hidden .header .block_action {

theme/bootstrapbase/less/moodle/course.less

@@ -317,7 +317,11 @@
     margin-top: 0;
 }
 .course-content ul li.section.hidden {
-    opacity: 0.5;
+    .sectionname,
+    .content > div,  /* All the divs but the activities which are in a UL. */
+    .activity .activityinstance {
+        opacity: .5;
+    }
 }
 .course-content ul.topics li.section .content,
 .course-content ul.weeks li.section .content {