fix dropdown style when input is shown

src/components/views/elements/Dropdown.js

@@ -310,7 +310,7 @@ export default class Dropdown extends React.Component {
         // 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}>
-            <AccessibleButton className="mx_Dropdown_input" onClick={this._onInputClick}>
+            <AccessibleButton className="mx_Dropdown_input mx_no_textinput" onClick={this._onInputClick}>
                 { currentValue }
                 <span className="mx_Dropdown_arrow"></span>
                 { menu }