Merge branch 'MDL-51451-m28' of https://github.com/sammarshallou/moodle…

… into MOODLE_28_STABLE

lib/yui/build/moodle-core-lockscroll/moodle-core-lockscroll-debug.js

@@ -71,6 +71,9 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
         this._enabled = true;
         var body = Y.one(Y.config.doc.body);
 
+        // Get width of body before turning on lockscroll.
+        var widthBefore = body.getComputedStyle('width');
+
         // We use a CSS class on the body to handle the actual locking.
         body.addClass('lockscroll');
 
@@ -83,6 +86,13 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
         Y.log("Setting the activeScrollLocks count from " + currentCount + " to " + newCount,
                 'debug', 'moodle-core-lockscroll');
 
+        // When initially enabled, set the body max-width to its current width. This
+        // avoids centered elements jumping because the width changes when scrollbars
+        // disappear.
+        if (currentCount === 0) {
+            body.setStyle('maxWidth', widthBefore);
+        }
+
         return this;
     },
 
@@ -109,6 +119,7 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
 
             if (currentCount === 1) {
                 body.removeClass('lockscroll');
+                body.setStyle('maxWidth', null);
             }
 
             body.setAttribute('data-activeScrollLocks', currentCount - 1);

lib/yui/build/moodle-core-lockscroll/moodle-core-lockscroll.js

@@ -68,6 +68,9 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
         this._enabled = true;
         var body = Y.one(Y.config.doc.body);
 
+        // Get width of body before turning on lockscroll.
+        var widthBefore = body.getComputedStyle('width');
+
         // We use a CSS class on the body to handle the actual locking.
         body.addClass('lockscroll');
 
@@ -78,6 +81,13 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
             newCount = currentCount + 1;
         body.setAttribute('data-activeScrollLocks', newCount);
 
+        // When initially enabled, set the body max-width to its current width. This
+        // avoids centered elements jumping because the width changes when scrollbars
+        // disappear.
+        if (currentCount === 0) {
+            body.setStyle('maxWidth', widthBefore);
+        }
+
         return this;
     },
 
@@ -103,6 +113,7 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
 
             if (currentCount === 1) {
                 body.removeClass('lockscroll');
+                body.setStyle('maxWidth', null);
             }
 
             body.setAttribute('data-activeScrollLocks', currentCount - 1);

lib/yui/src/lockscroll/js/lockscroll.js

@@ -69,6 +69,9 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
         this._enabled = true;
         var body = Y.one(Y.config.doc.body);
 
+        // Get width of body before turning on lockscroll.
+        var widthBefore = body.getComputedStyle('width');
+
         // We use a CSS class on the body to handle the actual locking.
         body.addClass('lockscroll');
 
@@ -81,6 +84,13 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
         Y.log("Setting the activeScrollLocks count from " + currentCount + " to " + newCount,
                 'debug', 'moodle-core-lockscroll');
 
+        // When initially enabled, set the body max-width to its current width. This
+        // avoids centered elements jumping because the width changes when scrollbars
+        // disappear.
+        if (currentCount === 0) {
+            body.setStyle('maxWidth', widthBefore);
+        }
+
         return this;
     },
 
@@ -107,6 +117,7 @@ Y.namespace('M.core').LockScroll = Y.Base.create('lockScroll', Y.Plugin.Base, []
 
             if (currentCount === 1) {
                 body.removeClass('lockscroll');
+                body.setStyle('maxWidth', null);
             }
 
             body.setAttribute('data-activeScrollLocks', currentCount - 1);