Setting up a variable condition for use onmousemove

Hello,

I'm having problems with a global variable.

I'm setting up $canDrawSpriteLine to true on a onmousedown event.

So, this function should work:

function SceneWindow2D::onMouseMove(%this, %mod, %worldPosition)
{
   if($canDrawSpriteLine $= true)
   {
   $position = %worldPosition;
   player.createline();
}
}

function player::createline(%this)
{
   %humo = new t2dParticleEffect()
   {
      sceneGraph = %this.scenegraph;
      class = "humo2";
   };
   %humo.loadEffect("~/data/particles/lineagis.eff");   
   %humo.setPosition($position);
   %humo.setEffectLifeMode("kill", 0.3);
   %humo.playEffect();   
}

And it is working and I can draw a sprite after sprite line, but the problem is that the $canDrawSpriteLine true condition is not recognized until a onmouseup event. And then the creation of sprites starts.

So, how can I do to set the variable as true to be recognized at the right moment -that is exactly after the onmousedown-?

Thanks