Use first vector source for OL3

src/components/modals/AddModal.jsx

@@ -66,7 +66,7 @@ class AddModal extends React.Component {
     if(!this.state.source && sourceIds.length > 0) {
       this.setState({
         source: sourceIds[0],
-        'source-layer': this.state['source-layer'] || nextProps.sources[sourceIds[0]][0]
+        'source-layer': this.state['source-layer'] || (nextProps.sources[sourceIds[0]] || [])[0]
       })
     }
   }

src/components/modals/SourcesModal.jsx

@@ -105,7 +105,6 @@ class ActiveSourceTypeEditor extends React.Component {
         borderWidth: 2,
         borderStyle: 'solid',
         padding: margins[1],
-        height: 50
       }}>
         <SourceTypeEditor
           onChange={this.props.onChange}