Chrome: 70 and newer
OS: Windows 7, and supposedly all others

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Repro:
1. install a devtools extension panel 
   https://chrome.google.com/webstore/detail/ocfjjjjhkpapocigimmppepjgfdecjkb
2. open devtools
3. switch to "Storage Explorer" tab in devtools toolbar
4. click "Add item"
5. click "Value"
6. press "?" key

Expected: "?" is shown
Observed: devtools settings UI is opened

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Bisected to r580011 = 9714881871a256c98e5b12651aedd5210319ef36 = crrev.com/c/1159467 by einbinder@chromium.org
"DevTools: Prevent browser behavior of shortcuts in extension panels"
Landed in 70.0.3511.0

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Note, arguably all single-letter keys without a modifier should not be intercepted by devtools in an extension panel regardless of whether the active element is a text input or not. The repro uses one just for an easy demo.