For peak usability, Windows 3.1 kept the mnemonics underlined _all the time_. It's been downhill since then. Though I'm looking at the menu bar on Firefox on Ubuntu right now and at least the mnemonics are underlined now as I type, even without hitting "alt".
Oh, man, I had forgotten about having the menu keyboard shortcuts underlined all the time. Sometimes you could even tell that whoever had a sense of humor in choosing the mnemonics. I don't even know how to open the macOS menu bar without my keyboard now.
After doing an Internet search for it, I have learned that it is Fn-Control-F2, after enabling Full Keyboard Access in Accessibility. How could it get this bad? (Apple's other accessibility features are amazing.)
I found screenshots on Mac OS very counter intuitive… why does it need to be 3 keys and one of which has the number 3 or 4 it? Why not 7 or 9 ? Or 1 or 5 ? Crazy
Back on the original Macintosh, which was a single-tasking system, there were special keyboard shortcuts that bypassed the current application and invoked system functions. Command-Shift-1 ejected a floppy from drive 1, …2 from drive 2, and …3 being the next available slot became the screenshot operation.
