Index: _source/plugins/wsc/dialogs/wsc.js
===================================================================
--- _source/plugins/wsc/dialogs/wsc.js	(.../tags/CKEditor.3.5)	(revision 325)
+++ _source/plugins/wsc/dialogs/wsc.js	(.../branches/3.5_disable_scayt_on_wsc_open)	(revision 325)
@@ -127,6 +127,20 @@
 		buttons : [ CKEDITOR.dialog.cancelButton ],
 		onShow : function()
 		{
+			// Destroy SCAYT instance on WSC window show (#6863)
+			var scayt_plugin = CKEDITOR.plugins.scayt;
+			if (scayt_plugin) {
+				var scayt_instance = scayt_plugin.getScayt( editor );
+				if ( scayt_instance )
+				{
+					scayt_plugin.setPaused( editor, !scayt_instance.disabled );
+					// store a control id for restore a specific scayt control settings
+					scayt_plugin.setControlId( editor, scayt_instance.id );
+					scayt_instance.destroy( true );
+					delete scayt_plugin.instances[ editor.name ];
+				}
+			}
+			
 			var contentArea = this.getContentElement( 'general', 'content' ).getElement();
 			contentArea.setHtml( pasteArea );
 			contentArea.getChild( 2 ).setStyle( 'height', this._.contentSize.height + 'px' );