File picker sometimes doesn't work in 2.7.9

[Who]

This is something I have only noticed with version 2.7.9 (if I revert to 2.7.8 I do not have the problem) and only with a very small subset of video files.  And really I have only seen it in the last two or three days, but there have not been any upgrades to MacOS in that time so I am not sure what causes it.  The problem is that once I have loaded a video to process, any operation involving the file picker doesn't work.  So for example, if I try to save a snapshot to the current frame, or add a logo, or save a project file, it will bring up the dialog for the operation I have selected but when I get to the point where I have to select a file (by clicking that button) it just sits there and the spinner spins for a while and goes away, and all I can do is hit cancel.  Starting over from scratch (closing Avidemux, which of course loses all my edits because I can't save a project file, and restarting it and reloading the file) does not help unless I go back to 2.7.8, in which case all works normally.  And I assume 2.7.8 is using the same preferences as 2.7.9, so the config change we made to eliminate the crash at the end of an encoding operation is still being used, otherwise I would suspect that as a possible cause.  So far I have seen this maybe three times since 2.7.9 came out, and unless you happen to know what you might have done in 2.7.9 that would affect the file picker you'll probably never figure it out because it happens so seldom, but it's a bad bug because when it does happen you will never be able to do anything with the affected file in 2.7.9.  And I am pretty sure it doesn't generate anything noteworthy in the log because no operation was completed - all the program probably knows (if it even records actions such as this) is that I attempted to select a file and then cancelled out, but of course the only reason I cancelled out was because it was the only thing I could do!

[eumagga0x2a]

This is something I have only noticed with version 2.7.9 (if I revert to 2.7.8 I do not have the problem) and only with a very small subset of video files. [...] The problem is that once I have loaded a video to process, any operation involving the file picker doesn't work. [...] Starting over from scratch (closing Avidemux, [...] restarting it and reloading the file) does not help unless I go back to 2.7.8, in which case all works normally.

Do these files have anything in common like location, container type, video codec, properties of audio tracks? Is this problem fully file-specific and reproducible? Does rebooting macOS help?

I went through a big collection of video files of different types (mp4, mkv, mpegts, mpegps, avi) using a big variety of codecs – load a file, open filepicker (Command+O), load the next one etc. + a couple of encodes, saving frames as JPEG and saving as project – and could not reproduce it with the latest official nightly so far.

So far I have seen this maybe three times since 2.7.9 came out, and unless you happen to know what you might have done in 2.7.9 that would affect the file picker

If you refer to the latest official macOS nightly (not a private build from the latest git master), there have been exactly zero changes which might affect the file dialog.

Your description lets me think of some Apple security mess (like if you build Avidemux Unix-style, i.e. not as an app bundle, and try to run it, the startup can take well over 20 seconds as macOS checks checksums of all files with the mothership, unless you switch to flight mode, which lets Avidemux start instantly).

And I am pretty sure it doesn't generate anything noteworthy in the log

Have you checked? The log contains not just stdout output of Avidemux but also stderr output of all involved libraries. I hope you have preserved at least one log from a session when the problem occured. If not yet, please do.

[Who]

Well the thing they have in common is they are all .ts files and I have had five of them in the last two days that were all essentially similar and two of them had this issue and the other three did not.  No I did not save the log because I can never remember where it is (I am old, my memory is not what it used to be) but also because I really did not think about it until after I had brought up 2.8 and started the encode there.  I was frustrated at the time this happened and just wanted to get the encoding started, and it was only as an afterthought that I thought maybe I should leave a post about this just in case it is really a problem that was introduced in the latest MacOS nightly.  If nothing has changed to affect the file picker then I have no idea why this happens in the 2.7.9 nightly and not in 2.7.8, and why just with certain files that are no different in structure from MANY other files I have encoded successfully.  If it happens again I will try to remember to save the log file (assuming I can find it again) but I will still be surprised if it shows anything useful.

EDIT: This issue disappeared in subsequent versions and I have not seen it at all in 2.8.0.