<p dir="auto">The validation works unexpected with my below steps to reproduce</p>
<h3 dir="auto">Expected results</h3>
<p dir="auto">The error "Control labeled "Metrics" cannot be empty" should not appear when delete Metrics</p>
<h3 dir="auto">Actual results</h3>
<p dir="auto">The error "Control labeled "Metrics" cannot be empty" appears when delete Metrics, but it not happens after refresh page</p>
<h4 dir="auto">Screenshots</h4>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/50986096/61705858-dbf94680-ad70-11e9-8c56-cba0c17dd09e.png"><img width="812" alt="Screen Shot 2019-07-23 at 5 39 08 PM" src="https://user-images.githubusercontent.com/50986096/61705858-dbf94680-ad70-11e9-8c56-cba0c17dd09e.png" style="max-width: 100%;"></a></p>
#### How to reproduce the bug
<ol dir="auto">
<li>
<p dir="auto">Go to 'Sources/Tables'</p>
</li>
<li>
<p dir="auto">Click on 'a table name'</p>
</li>
<li>
<p dir="auto">It goes to chart screen, with Table type</p>
</li>
<li>
<p dir="auto">Delete Metrics COUNT(*)<br>
=&gt; It's show the error similar to attachment.</p>
</li>
<li>
<p dir="auto">Try to select Columns on NOT GROUP BY or anything<br>
=&gt; The error not disappear</p>
</li>
<li>
<p dir="auto">Refresh page, and try to delete Metrics COUNT(*) again<br>
=&gt; The error does not appear</p>
</li>
</ol>
<h3 dir="auto">Environment</h3>
<ul dir="auto">
<li>superset version: Master branch on 2019, July 23</li>
<li>python version: 3.7.3</li>
<li>node.js version: 8.16.0</li>
<li>npm version: 6.4.1</li>
</ul>
<p dir="auto">PR <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="429372451" data-permission-text="Title is private" data-url="https://github.com/apache/superset/issues/7231" data-hovercard-type="pull_request" data-hovercard-url="/apache/superset/pull/7231/hovercard" href="https://github.com/apache/superset/pull/7231">#7231</a> updated visualization validation to take place in the exploreReducer.js <code class="notranslate">SET_FIELD_VALUE</code> action. This validation does not take into account any <code class="notranslate">controlOverrides</code> on the visualization.</p>
<p dir="auto">Specifically, the Table viz removes any validatation from the <code class="notranslate">metrics</code> row control. This means attempting to create a Table with only "Not Grouped By" columns fails.</p>
<h3 dir="auto">Expected results</h3>
<p dir="auto">Be able to create a Table visualization with only "Not Grouped By" columns</p>
<h3 dir="auto">Actual results</h3>
<p dir="auto">Creating any Table without a "Metrics" results in an error</p>
<h4 dir="auto">Screenshots</h4>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://user-images.githubusercontent.com/222699/56630031-623caa00-6615-11e9-815a-ff969664b2a2.png"><img src="https://user-images.githubusercontent.com/222699/56630031-623caa00-6615-11e9-815a-ff969664b2a2.png" alt="image" style="max-width: 100%;"></a></p>
<h4 dir="auto">How to reproduce the bug</h4>
<ol dir="auto">
<li>Create a Table Visualization</li>
<li>Delete "Group by" and "Metrics" values</li>
<li>Add "Not Grouped By" columns</li>
</ol>
<h3 dir="auto">Environment</h3>
<p dir="auto">Master branch as of April 22 (commit: <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https://github.com/apache/superset/commit/845218dd88ad2fe1284dcb7427c5bff20749dc74/hovercard" href="https://github.com/apache/superset/commit/845218dd88ad2fe1284dcb7427c5bff20749dc74"><tt>845218d</tt></a>)</p>
<h3 dir="auto">Checklist</h3>
<p dir="auto">Make sure these boxes are checked before submitting your issue - thank you!</p>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the superset logs for python stacktraces and included it here as text if there are any.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have reproduced the issue with at least the latest released version of superset.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the issue tracker for the same issue and I haven't found one similar.</li>
</ul>
<h3 dir="auto">Additional context</h3>
<p dir="auto">n/a</p>