Compass + css warnings

Hello

I have two issues/questions, I'm using phpstorm 7.1.3

1) I've just integrated compass with phpstorm. Most of the code is marked as valid but when I have:

  background: #e7e9ef image-url('small.jpg') no-repeat center center fixed;

IDE gives waring "Cannot find function image-url"

Is this normal behaviour or maybe I did something wrong? Other declarations as for example     @include background-size(100%);  dont' raise any warnings

2) In my SCSS file I have the following code:


    margin: calculateRemSize(1,$site-font-size) auto;
    margin: 1rem auto;

phpStorm IDE gives warning "Property margin is overwritten". Is it possible on per file basis to remove this one comment so whenever I open this particular file IDE will treat this code as valid (only those 2 above lines)?

Best regards