bug: leading Tab after Pre tag is stripped when saving

I tried to insert source code with Pre tag inside CKeditor v3.2, my code has leading Tab at the first line, I mean, every line of my code has indention. I copied the code from a php file and paste into the editor window, then I clicked the Save button, but CKeditor stripped off the leading Tab indention in first line!

I think this is a bug.

Please fix it. Thanks.