UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36

Steps to reproduce the problem:
1. Install latest verion of Adobe reader
2. The reader installs a plugin
3. Remove reader and plugin
4. Goto settings and click "clear auto-opening settings"

What is the expected behavior?
All settings should be cleared and the PDF should not be automatically opened after download.

What went wrong?
Some settings were not cleared and the PDF is still automatically opened. Clicking "clear auto-opening settings" repeatedly didn't work and the button did not go away.

Did this work before? No 

Chrome version: 55.0.2883.87  Channel: stable
OS Version: 10.0
Flash Version: 

I found a few settings in `\AppData\Local\Google\Chrome\User Data\Default\Preferences` file after clicking that button:

"download":{
  "extensions_to_open":"",
  "open_pdf_in_system_reader":false,
}

"plugins":{
  "always_open_pdf_externally":true,
}

As you can see, the settings in the download section are cleared as expected. However there is another setting in plugins, probably added by the adobe reader extension, and that setting is not removed or set to false.

I suspect clicking the "clear auto-opening settings" button doesn't check that setting.

I manually made these changes to that preferences file:

"plugins":{
  "always_open_pdf_externally":false
}

when I started the browser again the PDF was download and not automatically opened. Also that "clear auto-opening settings" button was gone from the settings page.