Stunner - apply correct highlight state to canvas elements

For the items that are rectangles, they'll need another rectangle like this:

the new one under the existing one, 6px stroke and the glow added on:
<rect class="highlightBorder" x="0" y="0" width="150px" height="98px" rx="2" ry="2" stroke="white" stroke-width="6px" filter="url(#highlightGlow)"/>
<rect class="task" x="0" y="0" width="150px" height="98px" rx="2" ry="2"/>

And for things like events or gateways that are a solid shape underneath, there should be a corresponding stroke on that solid layer. If the stroke comes out behind the border layer, then another layer behind the solid one can have the white stroke and glow filter.