It happens to me regularly that, after compiling a package, all blank lines disappear. The result looks like this:
The blank lines are still there, because they still have their line number. But their display is collapsed to 1 pixel high, or something like that.
Unfortunately I can't consistently reproduce this. But here's everything I know:
* This happens regardless of whether I use F8 or the toolbar icon.
* This only happens after a successful compilation, and never when there are compilation errors.
* After it happens, pressing Control-Z to undo the last edit fixes the display.
* After it happens, immediately compiling again (sometimes 2 or 3 times) fixes the display.
* It may be necessary to have a number of other windows open and the Window List displayed for it to happen.
I'd love to see this fixed, but I don't know what I can do to help you fix it. Please let me know if you have any ideas.
Version 15.0.4.2064 on Windows 10.