title: What could automatically toggle a checkbox in Unity's PluginInspector?
body: <p><strong>TL;DR</strong> <em>something is toggling a new platform's checkbox for a .dll in the plugin inspector behind my back.</em></p>
  
  <p>I am working on a cross-platform project, adding a new platform (I had to run an additional setup program for Unity to handle this new platform). I want to <strong>exclude a .dll library for this platform</strong>, because it is useless and also generates build errors on this new platform.</p>
  
  <p>I clicked on the .dll file and accessed the <strong>Plugin Inspector</strong> where "Any Plarform" is checked. Under "Exclude Platforms", I have <strong>toggled ON my new platform's checkbox</strong>, clicked on "Apply" and saved.</p>
  
  <p>That should have done the job... Alas, when I try to build the project, it looks like at some step <strong>the checkbox is toggled OFF</strong>, and I end up with the same build errors. This checkbox "reset" seems to also happen if I close Unity and open it again.</p>
  
  <p>What could be switching this checkbox's value against my will ? I have looked for <strong>OnPostprocessBuild and OnPreprocessBuild</strong> inside the Visual Studio's C# project, thinking maybe a script was forcing some values including resetting the ones for my new platform ; but none of the function I found seemed to manipulate this...</p>
  
  <p>What could be the origin of my problem ?</p>