Using the "Del" key whilst writing text in widget deletes the annotation

[EmKarr]

Hi there,

when adding text to an annotation (e.g. by entering it into the "Antwort schreiben" field on the demo at https://annotorious.github.io/getting-started/osd-plugin/, but also happens with my own editor widget), hitting the "del" key will instantaneously delete the whole annotation. This is not desirable whilst the text field has the focus, and maybe it would be a good idea to ask for user confirmation before deleting an annotation in general.

Thanks for your great work,
best,
Michael