"I agree with you that searching for only "^" or only "$" and "replacing" it with a string should be possible and I have already written that it works with UltraEdit and legacy Unix style."
Actually, I think it still works not very well with legacy UNIX style. As my example, if you replace "^" with a string one by one (not Replace All), you will get an unexpected result. I believe there is something bad with UE's algorithm. If you have time, you can test the same case with other text editor which support unix regex, then you can tell how I feel. I used to work with UE a few years ago, but since I learned unix regex and found the problem with UE, I gave up UE finally.
In certain aspect, UE is a good editor. I use unix regex a lot during my work and I really hope IDM can fix this problem so I can trust it again.