Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- config/locales/simple_form.pl.yml

app/javascript/mastodon/features/ui/index.js

@@ -259,6 +259,7 @@ class UI extends React.PureComponent {
     e.preventDefault();
 
     this.setState({ draggingOver: false });
+    this.dragTargets = [];
 
     if (e.dataTransfer && e.dataTransfer.files.length === 1) {
       this.props.dispatch(uploadCompose(e.dataTransfer.files));