I'm using new IGV version 3.0.4 with igv-webapp 2.0.0
The app seems to be trying to load the whole BAM file when loading a new track visualizing the whole chormosome.
This make the app unresponsive and block the browser.
This has been fixed (3.0.5 / 2.0.4). The bug was in igv.js, but igv-webapp bundles an igv.js version. I'm not sure how you got the combo 3.0.4 / 2.0.0.
I'm using new IGV version 3.0.4 with igv-webapp 2.0.0 The app seems to be trying to load the whole BAM file when loading a new track visualizing the whole chormosome. This make the app unresponsive and block the browser.