public boolean deleteSelected()
    {
        if (!handleSelectedPreModify()) {
            return false;
        }
        upANibble = 0;
        ensureWholeScreenIsVisible();
        restoreStateAfterModify();

        return true;
    }
While in insert mode, deletes the selection

@return did delete something
plugins/org.jkiss.dbeaver.ui.editors.hex/src/org/jkiss/dbeaver/ui/editors/binary/HexEditControl.java