title: How to control (active) tools in holoviews with bokeh backend
body: <p>How do I control which tools are used / active in a <code>holoviews</code> plot with the <code>bokeh</code> backend? I've seen <a href="https://stackoverflow.com/a/50416512/4880003">this SO answer</a>, but that only <em>adds</em> a new active tool; it doesn't keep any other tools (e.g. pan) from being active.</p>
  
  <p>For a specific example, suppose I only want the hover tool. I would try doing this:</p>
  
  <pre class="lang-py prettyprint-override"><code>import holoviews as hv
  hv.extension("bokeh")
  hv.Curve([1, 2, 3]).opts(tools=["hover"])
  </code></pre>
  
  <p>but then I end up with a plot that has hover <em>in addition</em> to the default tools. How do I specify the list of <em>all</em> tools that I want to use, so that no tools are used that aren't in that list?</p>
  
  <p><a href="https://i.stack.imgur.com/UM36Wm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UM36Wm.png" alt="plot with too many tools"></a></p>
  
  <p>Similarly, how do I specify the list of <em>all</em> active tools? E.g.</p>
  
  <pre class="lang-py prettyprint-override"><code>import holoviews as hv
  hv.extension("bokeh")
  hv.Curve([1, 2, 3]).opts(tools=["hover"], active_tools=[])
  </code></pre>
  
  <p>gives me both pan and hover being active; I want hover to be the only tool but no tool to be active.</p>
  
  <p><a href="https://i.stack.imgur.com/BtF7um.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BtF7um.png" alt="plot with too many active tools"></a></p>