Documentation / User interface / Modified files warning
Modified files warning
Generally, you should not edit your files in an external program during search or replace operation. It's hard to merge the concurrent edits, so your changes may be lost when you edit a file and, at the same time, replace in it.
If you edit a file after replacement and then press Undo button, Aba will warn you that your changes will be lost.
If you have some program for comparing and merging text files, you could use it to merge you changes into the undone file. Aba will run such program automatically if you chose to do so.
Aba will also show a warning if you searched for some pattern, then switched to external program and edited one of the found files, then switched back to Aba and pressed Replace button. In this case, the search will be repeated to show you the changes you have made.