Characters not in on-screen set silently eliminated

[amphigorius]

When entering character strings (for YouTube, but perhaps other places), only characters within the on-screen character set are copied to the on-screen field. If, for example, the string includes both numbers and letters, and the alphabetic table is showing, the copied string will have all of the letters but none of the numbers. Also there appears to be no way to edit the entered string short of backspace-deletion, so correcting the entered string can be tedious.
Thanks for all your work!