In the new "New Reddit" force-unloaded last year, there have been many (unfortunate) changes to post edit mode; one of them is that if you have several images and extra spaces between them, deleting even one such extra space sometimes inadvertently deletes the image above such spaces, even if there were, say, 4 spaces between images and you only deleted the bottom-most. Or sometimes it will delete any text above the line you just deleted if the spaces were between text and an image.

Here's the weird part (or at least for me it is): I inadvertently discovered by mistake that if you go to your DESKTOP menu and select "Undo" ... about 7/10 times it actually "undoes" the deletion within Reddit's edit mode and reposts any images/text lost.

How is this possible, ie, how do desktop OS functions work while editing in a website?