I have downloaded and installed the latest Web App Builder (WAB) version 2.7. When building an application and testing, I have noticed strange behavior with the icons that I did not have with version 2.6. I can make simple customizations, that work and have no errors or any issues in version 2.6, but there are issues in 2.7. Here is an example:
When the application loads (notice black lines over search widget):

The widgets are hidden over the search widget.
When the application is refreshed our the page size changes

There is something strange going on here. There are no errors in console mode and the issue has been replicated in Microsoft Internet Explorer 11 and Mozilla FireFox.