Almost every program stores what you write and then change or delete so that continuously pressing Ctrl-Z will restore everything you've changed or deleted up to a certain point. This means that each program that does this keeps a history of these changes, at least until you close the editing window you were working in.

I keep losing data in some programs that I spent a lot of time writing something by accidentally closing the editing window unless I save it to a text editor first, or a bug causes the program or my computer to freeze.

Is there any way to access that editing history if the program is still running and I just closed the editing window accidentally? I've since installed a clipboard history app but I'm trying to retrieve data from before I installed it, so it doesn't help in this case.

Any suggestions?

Some text editors have a .cache file that is left if the editor is not closed properly.

, maybe ~.kate-swp

or same directory you were working... .kate-swp

I hope this helps you progress.

Text editing widgets are only for entering small amounts of text.

Compose large amounts in a real text editor. Save it as needed. When you are done, copy-paste the text into your web browser or other application.
Ed

I was using an editor in an online social media site. I'm not sure what directory I was in at the time, but probably Home/. I always have hidden directories and file visible in the GUI (using Ubuntu 22.04 w/ Gnome), and I've never seen a .kate-swp.

BTW, I never said I was using a text editor. I said it happened in a text window in a program.

While the advice is good for text entry as described, it is even BETTER advice when you are talking an over complicated web site with "issues"! Social Media sites are less than optimal. They are only great at collecting and protecting the data you DON'T want them to have!

Are you sure about that?

Yes. Text editor widgets would have a "save" button if they had been intended for more input.
Ed

No doubt about that! It all starts with entering your email address or phone number.

Most text windows I've used DO have a save button. You say 'widget' while I'm talking about text windows. What you refer to would include text boxes in larger programs like Libre Writer. Even this text window I'm using here has a save button (Submit Reply).

Text windows can usually also handle relatively large amounts of data using Ctrl-Z / Shift-Ctrl-Z. This one does (just tested with a text file of 3920 characters I pumped in).

The "Submit Reply" button won't work if the network connection has been lost.

The text editor widget in your web browser and dialog boxes is a GtkTextView. Some websites add a Javascript editor. Neither of these is a substitute for a text editor with local storage.

You have exhausted my patience in only three posts. Just use the right program. The computer will work better.
Ed

If planning to enter a lot of text online, write it in an editor on your machine, copy & paste it into the online program, when you have written it all.

Have you recuperated yet?

I can just as easily lose my patience when someone responds to my question like you did and tells me one thing after another that's false and are so busy assuming the wrong things that you quickly exhausted yourself and are trying to blame it on me, and I feel justified to defend myself here instead of letting you blame me for your own mistakes while continuing to make more in this last response from you, all because you had a problem from the beginning in comprehending my OP. These new mistakes deserve being pointed out, and I can only hope that you'll accept your own faults and learn not to make the same kind of errors in the future. That will require you to slow down and read what's being asked, and not pretend that you know things you obviously don't.

1) I never said anything about losing a network connection, so you shouldn't assume that has anything to do with what I asked about in my OP.

2) I didn't say the problem was with my web browser either. I said in my OP that the problem has occurred with many of the programs I use, and in a later comment to someone else I said that the problem recently occurred on a social media site.

3) Web browsers don't typically have text editors built into them.

Now stop trying to answer questions that are beyond your ability to answer and do a few breathing exercises before you go into cardiac arrest.

Based on the replies here, it would appear that the answers are beyond your ability to understand. Because:

1. You never said what program(s) you were using, and didn't provide necessary information when asking. Where data/files are saved is far different for a website than it would be for any programming editor. Did you expect us to guess?
2. You say "many of the programs" (which ones??) and if your computer freezes/crashes/reboots, not sure how you'd expect things to be saved somehow.
3. Right, they don't, yet your problem seems to center around your comment of "I was using an editor in an online social media site".

Fatmac gave the correct advice, since entering information to an online site doesn't 'save' data in memory, but locally run editors do have cache files (which is how they CAN have an undo feature).

It could also be a plugin issue. I've ran into this type of occurrence and all that was required of me was to deactivate one or two plugins and hey presto the problem was fixed.