This is the same issue as 1759, I'm creating a new bug report as requested because it's still not fixed.
In brief, holding down the space bar to move the cursor past the left/right edge doesn't work when the search text doesn't fit in the search box. Instead of moving the cursor, it switches to selecting text.
Type something long in the search field so it scrolls past the left edge, then try to use the space bar to move the cursor back past the left edge.
