1,2) The file is 22GB, so uploading it isn't going to happen. But it's not the file, since every other video editor I've loaded the file into has handled it just fine, and I tried a couple other files and they did the same thing. Thinking maybe it was struggling with the file due to its size, I tried a smaller one (~600MB), which was slightly better, but not much. It still went unresponsive when trying to edit the time or do other things, it just didn't stay in that state as long (with the larger file, I eventually just killed it after waiting for a few minutes). But once it became responsive again, it would go unresponsive again within a few seconds, and this cycle just kept repeating. So there's clearly something wrong with the software. I then loaded a very small (~130MB) file, and that one seems to work ok.
3-4) As I said, HH:MM:SS.MS is the most common format used, and so this software should support it. This could be done in one of three ways: have it automatically replace the period with a comma when pasting it in, have a separate field for each format, or have it be an option that the user can set which format to use. Also, I don't see how to use ms instead of frame, as it won't allow me to change the semicolon to a comma. And if I type 22 in the seconds place then type a 2 (for the first place after the semicolon), it randomly changes it to 23;17. If I try to change the 3 to a 2, it changes it to 23;14. And so on. Very frustrating.
5) No. I'm talking about if I set a marker, then move it, sometimes it will just vanish, sometimes apparently clearing the selection, sometimes selecting everything. I think what's happening is it's jumping to the beginning, so if it's a start marker, this makes it so everything is selected, and if it's an end marker, it makes it so nothing is.
Also, something seems to have just happened with this website. It was working fine when I first checked your message yesterday, but then when I went to reply it "broke," requiring me to allow mixed content for it to load properly. I've never had to do that before for this site, but since yesterday it's been necessary.