Hello there, I have an idea for a feature request & I can only hope you see the possible use of it like I do.
I rely heavily upon expressions. I am not the best at constructing them nor making them streamlined, but I'm always looking for ways to make my library more efficient. It was the Rename, move & copy files dialogue box that got me thinking about this, and the fact you can specify flags in the making of custom fields, for example, you can make a custom field where the contained expression only evaluates upon image files, video files, etc., or a mixture of them by ticking checkboxes.
I use many expressions in the Rename, Move & Copy Files dialogue box. I store these expressions in custom fields. Which isn't the best way to do it, I imagine. I only do it to try and keep complexity down, rather than having mammoth expressions entered into the Rename move & copy files, dialogue boxes. It's slowing my library down as I believe these fields contained expressions are being evaluated upon every refresh of a view scheme or upon entering a view scheme. Their purpose has infrequent use. So they are continually being processed when not needed, which is highly inefficient for their purpose.
My idea and I can think of one other area of application, is that we coud possibly, in the making of custom fields, have a second flag type? A flag type that specifies which areas of Media Center itself in which and when the contained expressions of the fields are to be evaluated, like only when the Rename, move & copy dialogue box is open?
One other area, perhaps this could be useful in, is the media network. Expressions contained in fields to only be evaluated if and when there is an active connection to MCWS? Perhaps you can see more areas of Media Center in which flags like these could be used?