Interesting, it seems different from my experience, but maybe you mean something different, I can resize the preview window and it still has the correct behavior. Is that what you mean by 'user resizing the windows'? I wonder what is different.
Here's my example: gofile.io/d/qulRnW
The code is simple:
> let spriteInst = null
let spriteList= runtime.objects.Sprite.getAllInstances()
let mouseInst = runtime.objects.Mouse
for (let i=0;i<spriteList.length;i++)
{
spriteInst = spriteList[i]
if (spriteInst.containsPoint(mouseInst.getMouseX(),mouseInst.getMouseY()))
{
spriteInst.opacity = 0.5
} else
{
spriteInst.opacity = 1.0
}
}
That's definitely a working option, ain't thought of that. I was trying to determine the mouse position from the click event which seems to be your regular JS click.