DVWP greyed out in SPD 2013 for Pages using Custom Layout

I have a SharePoint 2013 site that has some custom branding and layouts. I need to add a DVWP to the Pages that have the custom layout applied, but the DVWP button in SharePoint Designer 2013 is greyed out.

This behavior only happens on Pages with custom layouts applied, I can create a non-customized Web Part Page in the Site Pages library and I have no problems adding the DVWP from SPD. I've tried to detach the page from the Page Layout in SPD and the option still remains greyed out. I'm sure I'm placing the cursor in the correct location.

I would use the non-custom webpart page but on these pages I don't have an option to change the page layout.

Any help will be appreciated.

Jovi