Seen on iOS.
On iPad, pressing Escape or Command + . when the file upload popover is open does nothing. But I would have expected it to dismiss the popover.
(*) On iPhone, pressing Command + . when the file upload picker is open does nothing. Pressing the Escape key dismisses the picker but now I cannot activate the picker again by tapping it. In fact, I can't even re-open the picker after reload. I needed to quit Safari!
Steps to reproduce (for those that can't be bothered to reads above or for machine in the all of us :D):
Ensure you have a hardware keyboard attached to your iPhone or iPad.
1. Visit <data:text/html,<input type="file">>
2. Tap the file input to open the picker/popup.
3. Press Escape on the keyboard (or Command + .)
Then nothing happens or you get into a bad state on iPhone (see remark (*)) if you pressed Escape. Anyway, the expected result is that the picker/popover is dismissed and you can re-activate it by tapping again.