i try to override the default key binding, on the user key binding, but i find that only changing the default helps.
for example: ctrl+c under Default/Default.sublime-keymap is:
<binding key="ctrl+c" command="copy"/>
and i place under User/Default.sublime-keymap
<binding key="ctrl+c" command="copy">
<context name="allSelectionsEmpty" value="false"/>
</binding>
well, it doesn’t work. only if i override the definition on Default/Default.sublime-keymap it works.