In the Edit > Find dialog, the “Replace” button not only replaces the currently found instance of the search string, but also then automatically jumps ahead to the next instance of the string, if any, even though the user did not request for Komodo IDE to perform another find operation. (Thus the button’s label is misleading and should instead read “Replace & Find”, as it does in jEdit.) This behavior is alright in the scenario when the user knows that there is only one instance of the search string — in which case it would not make sense to use the full find/replace dialog, but instead just do a quick find (the Fast Find feature) and then change the text manually. But more often than not, there are multiple instances of the search string within the file or the user does not know how many there are. When using a regex pattern, a user typically would like to verify that the replacement was done correctly — not in the sense that Komodo IDE might have interpreted the pattern incorrectly but rather that the user may have entered one that does not do exactly what he hopes it will (we’ve all been there!). If the next instance of the search string is more than a screenful of text below the first, then the result of the previous replacement is no longer immediately visible, and the user may not discover that there was a problem with it. A diligent individual is thereby forced to backtrack to the previous replacement — perhaps by changing the search string (to match the replacement value) and then searching backwards, which adds an extraneous entry to the “Find” field. All of these problems would be avoidable if the dialog had a new button that would perform a replace operation and then stay put, so the user can see the replacement before optionally searching for the next instance. (Further discussion at https://github.com/Komodo/KomodoEdit/issues/2483.)
As has been said in the issue, when doing regex-based replacements with groups, first I’d want to see what I’ll get (I often do mistakes in my regexes because Lords of the Regex Lands hates me). Copying the whole document to the regex editor just to test my regex is weird and Komodo Edit does not have the regex editor at all.
A preview of some sort would be a cool idea.