From b95b05085c1ee1e68f275186acef77cb2a9dcd1d Mon Sep 17 00:00:00 2001
From: Andrew Robert Nicols <andrew.nicols@luns.net.uk>
Date: Mon, 11 Jun 2012 08:18:44 +0100
Subject: [PATCH] MDL-33649 Hide page scrollbars when a chooser is open

This has the effect of preventing page scrolling which makes the chooser
difficult to use when there are many options or the page is too small.
---
 lib/yui/chooserdialogue/chooserdialogue.js | 31 ++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/lib/yui/chooserdialogue/chooserdialogue.js b/lib/yui/chooserdialogue/chooserdialogue.js
index 7f720d26026..bd29b818770 100644
--- a/lib/yui/chooserdialogue/chooserdialogue.js
+++ b/lib/yui/chooserdialogue/chooserdialogue.js
@@ -17,6 +17,9 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
         // Any event listeners we may need to cancel later
         listenevents : [],
 
+        // The initial overflow setting
+        initialoverflow : '',
+
         setup_chooser_dialogue : function(bodycontent, headercontent, config) {
             // Set Default options
             var params = {
@@ -65,6 +68,14 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             var bb = this.overlay.get('boundingBox');
             var dialogue = this.container.one('.alloptions');
 
+            // Get the overflow setting when the chooser was opened - we
+            // may need this later
+            if (Y.UA.ie > 0) {
+                this.initialoverflow = Y.one('html').getStyle('overflow');
+            } else {
+                this.initialoverflow = Y.one('body').getStyle('overflow');
+            }
+
             var thisevent;
 
             // These will trigger a check_options call to display the correct help
@@ -168,9 +179,21 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
             // Set a fixed position if the window is large enough
             if (newheight > this.get('minheight')) {
                 bb.setStyle('position', 'fixed');
+                // Disable the page scrollbars
+                if (Y.UA.ie > 0) {
+                    Y.one('html').setStyle('overflow', 'hidden');
+                } else {
+                    Y.one('body').setStyle('overflow', 'hidden');
+                }
             } else {
                 bb.setStyle('position', 'absolute');
                 offsettop = Y.one('window').get('scrollTop');
+                // Ensure that the page scrollbars are enabled
+                if (Y.UA.ie > 0) {
+                    Y.one('html').setStyle('overflow', this.initialoverflow);
+                } else {
+                    Y.one('body').setStyle('overflow', this.initialoverflow);
+                }
             }
 
             // Take off 15px top and bottom for borders, plus 40px each for the title and button area before setting the
@@ -203,6 +226,14 @@ YUI.add('moodle-core-chooserdialogue', function(Y) {
         hide : function() {
             // Detach the global keypress handler before hiding
             Y.one('document').detach('keyup', this.handle_key_press, this);
+
+            // Re-enable the page scrollbars
+            if (Y.UA.ie > 0) {
+                Y.one('html').setStyle('overflow', this.initialoverflow);
+            } else {
+                Y.one('body').setStyle('overflow', this.initialoverflow);
+            }
+
             this.container.detachAll();
             this.overlay.hide();
         },