Walking animation 'on the spot' with certain key presses

Got it in the wrong forum last time...

I have a glitch in my code somewhere, and was wondering if one of you kind souls would help me.

I have a walking animation frame for a movieclip (frame 5), and a still frame for when it is not in motion (frame 1).

It all works fine, except for one small glitch.

If I hold RIGHT (for example), then release, it stops walking.
If I hold RIGHT, then hold UP, then release UP, then release RIGHT, it continues the walking animation but stops moving.

Any ideas?

Code:

---

onClipEvent (load) {
        gotoAndStop(1);
    leftpower = 12;
    rightpower = 12;
    uppower = 12;
        downpower = 12;
}
onClipEvent (enterFrame) {
        if (Key.isDown (Key.CONTROL))
        {
                keydown=true;
                        }
        else
                keydown=false;

    if (Key.isDown(Key.LEFT)) {
        _x -= leftpower;
                gotoAndPlay(5);
                        this._xscale = -100;
    }
    if (Key.isDown(Key.RIGHT)) {
        _x += rightpower;
                gotoAndPlay(5);
                        this._xscale = 100;
    }
    if (Key.isDown(Key.CONTROL)) {
        gotoAndPlay(12);
    }
    if (Key.isDown(Key.UP)) {
        _y -= uppower;
                gotoAndPlay(5);
    }
    if (Key.isDown(Key.DOWN)) {
        _y += downpower;
                gotoAndPlay(5);
    }
        if (_root.wall.hitTest(_x, _y, true)) {
        xspeed = 0;
        yspeed = 0;
                leftpower = 0;       
    }
        else {
                leftpower = 12;
        }
        if (_root.bwall.hitTest(this.touch)) {
        xspeed = 0;
        yspeed = 0;
                downpower = 0;       
    }
        else {
                downpower = 12;
        }
                if (_root.twall.hitTest(this.touch)) {
        xspeed = 0;
        yspeed = 0;
                uppower = 0;       
    }
        else {
                uppower = 12;
        }
          if (_root.leadpipe.leadpipetouch.hitTest(this.touch)) {
        _root.leadpipe._x = -1000
                gotoAndPlay(5);

    }
}
onClipEvent (keyUp) {
  if (Key.getCode() == Key.RIGHT) {
      gotoAndPlay(1)
  }
}
onClipEvent (keyUp) {
  if (Key.getCode() == Key.LEFT) {
      gotoAndPlay(1)
  }
}
onClipEvent (keyUp) {
  if (Key.getCode() == Key.UP) {
      gotoAndPlay(1)
  }
}
onClipEvent (keyUp) {
  if (Key.getCode() == Key.DOWN) {
      gotoAndPlay(1)
  }
}

---

After playing about, I think I've narrowed it down to this (again, this is an example, because whether you press a combination of up, down, left, or right - the glitch still appears):

Code:

---

onClipEvent (keyUp) {
  if (Key.getCode() == Key.UP) {
      gotoAndPlay(1)
  }
}

---

Works fine on its own, but when combined with right, for example, it doesn't seem to gotoAndPlay frame 1, it just continues to play frame 5.

I'm thinking maybe

I finally got it!

Code:

---

        if (Key.isDown(Key.LEFT) == false && Key.isDown(Key.DOWN) == false && Key.isDown(Key.RIGHT) == false && Key.isDown(Key.UP) == false) {
gotoAndStop(1);
        }

---