Index: _source/plugins/wysiwygarea/plugin.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- _source/plugins/wysiwygarea/plugin.js	(revision 7430)
+++ _source/plugins/wysiwygarea/plugin.js	(revision )
@@ -779,14 +779,14 @@
 							{
 								if ( CKEDITOR.env.gecko )
 								{
-									var scroll = domWindow.getScrollPosition();
+									var body = domDocument.getBody();
+
 									// Page up/down cause editor selection to leak
 									// outside of editable thus we try to intercept
 									// the behavior, while it affects only happen
 									// when editor contents are not overflowed. (#7955)
-									if ( !scroll.y )
+									if ( domWindow.$.innerHeight > body.$.offsetHeight )
 									{
-										var body = domDocument.getBody();
 										range = new CKEDITOR.dom.range( domDocument );
 										range[ keyCode == 33 ? 'moveToElementEditStart' : 'moveToElementEditEnd']( body );
 										range.select();