I want to learn one thing. While searching in all logs, if we press on Ignore button when it prompts us to enter a password for encrypted files, does the search function skip the .ple files or does it search them without decrypting at all?
Continue reading if you are calm and fine. Because even me have difficulties understanding what I mean in these paragraphs 
Also I want to mention one thing about my suggestion. You said multiple popups were quite annoying and now I agree with you (volv's suggestion would be cool really). However for each new search, it asks the password again. If you press on Ignore button for the second and later searches without typing the password again, it can decrypt the files again with the password in memory which remains from the first search. Then why does it ask it again? I think this is the actual annoying thing.
When one password is input while the Log Viewer is open, then all the files which are encrypted with that password can be decrypted without entering the password again unless you need and enter another password for a new encrypted file which has been encrypted with another password, I mean Log Viewer can always remember one password at its memory. Even when you opened an encrypted file in the log viewer, and then when you want to search in all logs, even if you press on Ignore button when it prompts, it can still decrypt the encrypted files with the password in memory. But the reverse mechanism doesn't work. When you searched in all logs and entered a password to search in all logs, after the search is finished, when you click on a result file, it asks the password again. Why? If you didn't know the password, you couldn't search in that file and find that file anyway. Please consider these improvements for next version.
Edit: Also search function cannot find some words or word sequences which are formatted with a gradient effect.
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