Precision transform (holding shift) is not working at all

Question

When you are moving/rotating something in 3D, you're supposed to be able to hold shift for the precision mode where things move more slowly.

https://docs.blender.org/manual/en/latest/scene_layout/object/editing/transform/control/precision.html

That is no longer working for me, after upgrading to a new blender version. I've made sure snapping is off, but it's still no good; holding shift has no effect.

I'd appreciate any help with this. I'm sure I'm missing something obvious.

Edited to add: Reverting to the default keymap makes precision mode work again, but it doesn't work with my own key bindings. But it's supposedly hard-coded, and I have nothing bound to shift.

Other than manually writing down and re-entering hundreds of key bindings, does anyone have any thoughts as to what I might do?

Answer 1

I found the problem. Hidden away at the bottom of the key mapping list is the "Transform Modal Map" category. If you add a new binding to that category, "Precision mode" is an option, even though that doesn't show up when you search binding names for some reason.

Answer 2

These values seem to be hard-coded into the transform operator in C.I don't think there is a way to change it outside of writing a custom transform operator in Python or a custom build of Blender.

eRedrawFlag handleMouseInput(TransInfo *t, MouseInput *mi, const wmEvent *event)
{
  eRedrawFlag redraw = TREDRAW_NOTHING;

  switch (event->type) {
    case EVT_LEFTSHIFTKEY:
    case EVT_RIGHTSHIFTKEY:
      if (event->val == KM_PRESS) {
        t->modifiers |= MOD_PRECISION;
        /* shift is modifier for higher precision transforn */
        mi->precision = 1;
        redraw = TREDRAW_HARD;
      }
      else if (event->val == KM_RELEASE) {
        t->modifiers &= ~MOD_PRECISION;
        mi->precision = 0;
        redraw = TREDRAW_HARD;
      }
      break;
  }

  return redraw;
}
```