On iOS, Command + . maps to Escape. Currently the behavior of Command + . differs whether the key events are dispatched to an editable or non-editable element. We want Command + . to behave as if the Escape key was pressed for key events dispatched to non-editable elements.
You can observe this difference by using a hardware keyboard and performing the following:
1. Visit <https://unixpapa.com/js/testkey.html>.
2. Ensure Modifiers and DOM 3 attribute values are enabled.
3. Press Command + . on the keyboard.
4. Focus the text field.
5. Press Command + . on the keyboard.
Compare the logged output emitted after (3) and (4).
As it turns out, the behavior is correct. We want Command + . to dispatch be treated as key events for Command and key events for '.'. I am going to make behavior of pressing Command + . in a non-editable element match the behavior for the editable case (see bug #193255).