message: Fix dropdown keyboard accessibility when filter is disabled
diff: @@ -204,7 +204,7 @@ export default class Dropdown extends React.Component<IProps, IState> {
  this.props.onOptionChange(dropdownKey);
  };
  - private onInputKeyDown = (e: React.KeyboardEvent) => {
  + private onKeyDown = (e: React.KeyboardEvent) => {
  let handled = true;
  // These keys don't generate keypress events and so needs to be on keyup
  @@ -320,7 +320,6 @@ export default class Dropdown extends React.Component<IProps, IState> {
  type="text"
  autoFocus={true}
  className="mx_Dropdown_option"
  - onKeyDown={this.onInputKeyDown}
  onChange={this.onInputChange}
  value={this.state.searchQuery}
  role="combobox"
  @@ -358,7 +357,7 @@ export default class Dropdown extends React.Component<IProps, IState> {
  // Note the menu sits inside the AccessibleButton div so it's anchored
  // to the input, but overflows below it. The root contains both.
  - return <div className={classnames(dropdownClasses)} ref={this.collectRoot}>
  + return <div className={classnames(dropdownClasses)} ref={this.collectRoot} onKeyDown={this.onKeyDown}>
  <AccessibleButton
  className="mx_Dropdown_input mx_no_textinput"
  onClick={this.onInputClick}
  