First thing, thank you for the program. I switched from ditto after a few years of using it, since Ethervane Echo covers some of the problems I had with it, without losing anything that I really used. So far, after a few weeks of testing it, it seems to work very well.
I do have a feature request, relating to the option not to store clips from certain programs (one of my issues with ditto).
For most cases basing this on the application is the right thing to do and exactly what is needed. But there are cases where it would be nice to be able to selectively not store a clip based on part of the title too (well, based on the context, but title is the only technically feasible way to do that usually), and not for the entire program.
I don't think it's a widespread need, but there are some cases where it will make my life a bit easier (some, though happily not all, of the examples above), and I think it's also not that rare.
Adding to the application filter list some way to add modifiers to the program name, which must exist on the title of the window copying from, would probably be good enough.
I'm not sure if it's a good idea to also allow a title filter for all programs or not. On the good side it will work for websites when using multiple browsers, or documents that may be opened with multiple programs. But on the other hand it will probably complicate things, it will increase the chance of accidental matches, and realistically I think any file of website with sensitive information is probably not opened with more than one, or maybe two, programs on a regular basis.