This is an addition to the base EmailValidator in flex. This in addition to EmailValidator triggers error if an email address is already present in a given data provider.
Note: As of now it only supports ArrayCollection as data provider. You may update the code accordingly for your use.

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Most of the results found on net were disappointing. Since they just provided a solution to place the ComboBox  on datagrid header. The basic step was to override the setter function data in ComboBox class which is intended to be the DataGridHeader Renderer

override public function set data(value:Object):void
{
	if(value is DataGridColumn)
	{
		//Don't do anything
	}
        else
	{
		super.data = value
	}
}

Unfortunately, it didn’t really work well. The values in ComboBox never remained the selected once after it was sorted. After digging in to the main classes I came up with a solution.

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“Internet explorer cannot download….
Internet explorer was not able to open this internet site. …”

All the other browsers were able to download the file with out any issues.

I googled with the error string and found several suggestions, most of them being over the protocol  “https”, but for me it was “http”. And the results suggested to make a change in IE settings . My client cannot go over his customers and say that the settings on IE should be changed to download the file.

This link suggested a solution – http://support.microsoft.com/kb/812935

This issue may occur if any one or more of the following conditions are true:

• The Do not save encrypted pages to disk check box is selected in Internet Explorer 6.0 SP1.
• The server sends the “Cache-Control: No Store” header.
• The server sends the “Cache-Control: No Cache” header.

Well, all that I have to do was to send an updated header from my page in php

header('Content-type: application/pdf');
header('Cache-Control: cache, must-revalidate');
header('Pragma: public'); 

It resolved the issue for me .