Modal, state, update, ??

I have created an Imageslider component. I feed it a list of images. It works like a charm. I also can give it a property currentImage and when I use it like

<ImageSlider images={images} currentImage={this.state.currentImage} ref='slider'/>

It works like a charm. The sliding is basically a ScrollView that slides to a new position.

In that component I created a function slideTo(id) which slides to the image.
I can slide to images by setting the prop or by calling this.refs.slider.slideTo(10).

When I place the ImageSlider in a Modal it stops sliding.
I have added a <Text>{this.props.currentImage}</Text> to the ImageSlider to see if it gets updated when the currentImage in the state is changed and that works. The componentDidUpdate is fired however both this.props and prevprops are equal.

Anyone any clue what might be the problem?