I'm trying to use different `isolate-grid()` settings at multiple breakpoints like so:

Markup:

```
<div class="boxes">
  <div class="box">
    Box 1
  </div>
  <div class="box">
    Box 2
  </div>
  <div class="box">
    Box 3
  </div>
  <div class="box">
    Box 4
  </div>
  <div class="box">
    Box 5
  </div>
  <div class="box">
    Box 6
  </div>
</div>

```

SASS:

```
$total-columns: 4;
$column-width: 60px;
$gutter-width: 40px;
$grid-padding: $gutter-width / 2;
$container-style: fluid;
$container-width: 940px;

%container {
  $include container;

    @include at-breakpoint(9) {
      @include set-container-width;
    }

    @include at-breakpoint(12) {
      @include set-container-width;
    }
}

.boxes
  @extend %container;

  .box {
    @include isolate-grid(2);

    @include at-breakpoint(9) {
      @include isolate-grid(3,9);
    }

    @include at-breakpoint(12) {
      @include isolate-grid(4,12);
    }
  }
}

```

However, even though the column spans adjust as expected, the omegas don't seem to get reset correctly and so some of the boxes get cleared and don't appear on the same row.

I'm sure I've missed something obvious, but I've been going round in circles for ages now! I've tried adding in various combinations of `reset-omega()` and `reset-columns()` but no joy as yet.

Any ideas to put me out of my misery?!

Regards,

Matt.