diff --git a/app/javascript/mastodon/features/compose/components/poll_form.js b/app/javascript/mastodon/features/compose/components/poll_form.js
index 211601d52..898f956b0 100644
--- a/app/javascript/mastodon/features/compose/components/poll_form.js
+++ b/app/javascript/mastodon/features/compose/components/poll_form.js
@@ -142,9 +142,7 @@ class PollForm extends ImmutablePureComponent {
         </ul>
 
         <div className='poll__footer'>
-          {options.size < 4 && (
-            <button className='button button-secondary' onClick={this.handleAddOption}><Icon id='plus' /> <FormattedMessage {...messages.add_option} /></button>
-          )}
+          <button disabled={options.size >= 4} className='button button-secondary' onClick={this.handleAddOption}><Icon id='plus' /> <FormattedMessage {...messages.add_option} /></button>
 
           <select value={expiresIn} onChange={this.handleSelectDuration}>
             <option value={300}>{intl.formatMessage(messages.minutes, { number: 5 })}</option>
diff --git a/app/javascript/styles/mastodon/components.scss b/app/javascript/styles/mastodon/components.scss
index 417e8c899..ded668aea 100644
--- a/app/javascript/styles/mastodon/components.scss
+++ b/app/javascript/styles/mastodon/components.scss
@@ -392,6 +392,7 @@
   .autosuggest-input,
   .spoiler-input {
     position: relative;
+    width: 100%;
   }
 
   .spoiler-input {