Cursor vanishes when tapping spacebar

Unless I'm mistaken, this is normal. It occurs whenever you hit any key on the keyboard for text entry, and is based around the idea that you're typing, and probably don't want the cursor to obscure what you're typing.

That's been the case for as long as I can remember. Are you saying something's different?

> but when I want to press the spacebar to move the cursor along the line for whatever reason,

... do you mean the mouse cursor, or the insertion point?

I was referring to the mouse cursor, which has always gotten out of the way when you start typing, but it sounds like you're referring to the insertion point (where the next character you type will appear)... that's a whole different thing. I wouldn't expect that to disappear, since it's kind of critical to know where you're about to type :)