Tiff viewer zooms to center of screen, not center of image

[mvdbeek]

Use https://test.galaxyproject.org/datasets/682608ee89b31b36 and if you try to zoomin via the buttons it just zooms towards the center of the screen

[davelopez]

@mvdbeek do you expect something like this? galaxyproject/galaxy-visualizations#152

[mvdbeek]

Yes, that looks great!