title: How to align x-axis scale on two concatenated graphs in Vega Lite
body: <p>I have a chart composed with <code>vconcat</code> and <code>layer</code>. The layered plot is one of the blocks in the vertical concatenation, it plots two different datasets. There are two more blocks in the vconcat: one that has a different (third) dataset, and another that is a smaller version of one of the layers (used for brushing / zoom). The x scales of all the charts follow the selection via brush signal; the bottom chart sets the signal value via user interaction.</p>
  <p><a href="https://i.stack.imgur.com/Ujp64.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ujp64.png" alt="enter image description here" /></a></p>
  <p>I would like to align the x-axes on all the vconcat chunks. The dataset of the mis-aligned one does not cover as much as the timeseries line (it starts and ends around where the vertical dashed lines are).</p>
  <p>When zooming / brushing with the bottom chart, the axes align. When the chart first loads, each x-axis covers the extent of the matching dataset. I'd like the axes to cover the largest extent of all the layers / concat blocks.</p>
  <p>I've tried using the resolve config, &quot;shared&quot; vs &quot;independent&quot; etc, with no success.</p>