Few things:
You do not need type='file'an IconButton, just an input
IconButton does not expect its children to be anything other than SVGIcon, so I recommend that you use a regular button
I would not call stopPropagation in this case
You have a typo in your input support type. You have one type="file type='file'. It should be easytype="file"
So, all together:
<FlatButton label="Choose file" labelPosition="before">
<input type="file" style={styles.exampleImageInput} />
</FlatButton>
, , , , - <input> FlatButton .