I need a tab in tools->options window.if we click on that tab it should give 2 text fields one with some default file extensions seperated by semicolon and another text field with valid extensions seperated by semicolon which should be editable i.e user can add/delete an extension to it.for that i need 2 buttons called add,delete.If we click on add it should give a editable text field.we can enter the name of the extension and then press ok.for that i need 2 buttons ok and cancel.After that it will be immediately added to the text field which containes valid extensions. If he click on cancel button instead of ok button then that given extension should not add to the list of valid extensions.If user want to delete any extension then he should click on delete button then it will give a dropdown textfield with all valid extensions,user should select one extension among them and then he should click on ok button.It should immediately update the valid text field by removing the deleted extension.If he click on cancel button instead of ok button then that selected object should not delete.Can you please provide me c#.net coding for this requirement.