Window trim can be plain or fancy, stock or custom, layered or flat. There are even windows without any trim at all.
When walking into a customers home for the first time design professionals will scope out the window trim or casings and start an internal dialogue with themselves...
"How will I install when there is no wall above the window?,
"Will the customer allow me to put screws in the trim?,
"Can I outside mount"?
"Is there room to inside mount"?
Many times the homeowner is proud of their trim work. Perhaps it is custom, an important part of an historic interior or they find the wood attractive. There are choices for inside mounting that will leave the window trim exposed.
The cornice below (from House Beautiful) is a great example of an inside mount style that leaves all the trim work exposed. The photo above from designer Abbey K (www.abbeyk.com) is a great example of how use soft shaped valances combined with pull down shades all in a color that compliments the beautiful wood work.
Take care when measuring to establish good proportions. It is more difficult with inside mount top treatments because they can seem too short but make them too long and they will appear to take up too much of the upper portion of the window. A paper cut out of the valance shape can be taped inside the window to give a good impression of how the finished valance will look.
Shades such as Roman or Austrian styles are a good choice for inside mount and will provide a working window treatment with all the beautiful moldings exposed around the window.