Commenter Adam S wonders why holding the
It's a rogue feature.
Windows XP introduced visual styles, and one of the tricky parts of debugging visual styles is that if the visual style engine goes berzerk, you can't see anything! One of the problems that the visual styles folks encountered when developing their feature was that sometimes they would get into a state where the Run dialog would stop working. And without a Run dialog, you couldn't install or launch a debugger to begin investigating what went wrong.
The solution: Add the rogue feature where holding the
Over time, the bugs in the visual style system got worked out, and this rogue escape hatch was no longer needed, but for whatever reason, it never got removed.