New Wiki page Error

When you have your own custom master page in SharePoint 2010, maybe you’d come up with this issue when saving a simple wiki page in Site Pages or a Wiki library.

“you must specify a value for this required field”

I googled and found the reason is because of a missing folder which I had removed (better to say hided incorrectly). and it is this place holder:

<asp:ContentPlaceHolder id=“PlaceHolderPageTitleInTitleArea” runat=”server”></asp:ContentPlaceHolder>


What I had done was I had put this code inside an ASP Panel and set the visibility of the panle to hidden.
I found that I should do this with CSS like this.

<asp:Panel runat="server" CssClass="hidden" >
...
<asp:ContentPlaceHolder id="PlaceHolderPageTitleInTitleArea" runat="server" />
...
</asp:Panel>


I found these posts helpful :

http://alispasset.blogspot.co.uk/2011/11/you-must-specify-value-for-this.html

http://borderingdotnet.blogspot.co.uk/2010/09/you-must-specify-value-for-this.html